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LABORATORY  EXERCISES 


IN 


GENERAL  ZOOLOGY 


BY 


GLENN   W.   HERRICK,  B.S.A. 

PROFESSOR    OF   BIOLOGY   IN   THE    MISSISSIPPI   AGRICULTURAL 
AND   MECHANICAL   COLLEGE 


NEW  YORK-:.  CINCINNATI-:.  CHICAGO 

AMERICAN    BOOK    COMPANY 


COPTEIGHT,    1907,   BY 

GLENN  W.  HEKRICK. 


EX.   IN   GEN.    ZOOLOGY. 
W.  P.    I 


BIOLOGY 

LIBRARY 
G 


PREFATORY  NOTE 

THE  following  outline  of  work  in  practical  zoology  is 
intended  to  be  flexible  both  in  material  and  iii  order  of 
presentation.  Material  may  be  added  or  eliminated  and 
the  order  of  presentation  may  be  changed  to  suit  the 
conditions  of  the  school  or  the  views  of  the  instructor. 
As  it  stands,  it  represents  the  author's  idea  of  the  general 
nature  and  extent  of  a  course  in  practical  zoology,  that, 
when  supplemented  by  the  text,  will  constitute  a  knowl- 
edge of  animal  life  that  should  occupy  its  proportionate 
share  in  the  education  of  a  well-rounded  person  in  the 
ordinary  pursuits  of  life.  The  author  has  attempted  to 
combine  Huxley's  "verification"  method  with  Agassiz's 
"  investigation  "  method  in  such  proportions  as  to  main- 
tain interest,  cultivate  scientific  habits  of  thought,  and 
impart  lasting  information. 

Some  do  not  think  it  best  to  begin  with  the  microscope, 
but  the  author's  experience  indicates  that  high  school 
pupils,  sufficiently  advanced  to  take  a  course  in  zoology 
equivalent  to  the  one  outlined  here,  learn  to  use  the 
microscope  as  easily  in  the  early  part  of  the  course  as  in 
its  later  stages.  Pupils  of  this  age  are  so  interested  and 
enthusiastic  over  the  wonders  of  microscopic  life  that  they 
are  eager  to  learn  to  use  the  microscope  and,  with  few 
exceptions,  handle  the  instrument  with  skill  and  fine  care, 
often  verging  on  solicitude. 

Also,  some  teachers  prefer  to  begin  the  subject  of 
zoology  with  the  study  of  one  of  the  higher  animals ;  for 

3 

255373 


4.  PREFATORY  NOTE 

example,  a  grasshopper,  crayfish,  or  bird.  To  meet  this 
view,  each  of  the  laboratory  exercises  practically  stands 
as  a  unit,  and  any  one  of  the  above  animals  may  be  used 
to  introduce  the  subject  if  desired;  but  the  exercise  on 
the  grasshopper  is  designed  especially  for  introductory 
work.  Moreover,  there  is  sufficient  unity  in  the  treat- 
ment in  the  text  of  the  groups  of  animals  represented  by 
the  foregoing  examples  to  make  such  a  method  perfectly 
feasible. 

GLENN  W.   HERRICK. 


CONTENTS 


PRELIMINARY  EXERCISES 


.     I. 

USE  OF  THE  MICROSCOPE       

7 

II. 

10 

III. 

THE  CLASSIFICATION  OF  ANIMALS        .... 

11 

IV. 

PLANT  CELLS  

14 

V. 

ANIMAL  CELLS         

16 

STUDIES   OF   ANIMAL  TYPES 

VI. 

A  SIMPLE  MARINE  SPONGE  (GRANTIA) 

21 

VII. 

THE  FRESH-WATER  HYDRA   

23 

VIII. 

A  CAMPANULARIAN  HYDROID        

25 

IX. 

THE  STARFISH         

26 

X. 

THE  EARTHWORM   

30 

XI. 

THE  RIVER  MUSSEL        

34 

XII. 

THE  SQUID       ......... 

39 

XIII. 

THE  HABITS  AND  LIFE  HISTORY  OF  A  POND  SNAIL 

40 

XIV. 

THE  CRAYFISH        

42 

XV. 

OTHER  CRUSTACEANS      

47 

XVI. 

THE  LOCUST  OR  GRASSHOPPER      

48 

XVII. 

THE  CABBAGE  BUTTERFLY     

55 

XVIII. 

THE    MOUTH    PARTS    AND    LIFE    HISTORY    OF    THE 

SQUASH  BUG  AND  THE  HARLEQUIN  CABBAGE  BUG 

59 

XIX. 

THE  COMMON  AND  MALARIAL  MOSQUITOES 

61 

XX. 

THE  PERCH      

66 

XXI. 

THE  FROG       .        .        .        

71 

XXII. 

THE  LIZARD    ......... 

77 

XXIII. 

THE  ENGLISH  SPARROW         

82 

XXIV. 

THE  GRAY  RABBIT,  OR  COTTON  TAIL 

87 

APPENDIX 

95 

M 


FIG.  1. — Microscope;  G,  eyepiece;  J,  coarse  adjustment;  K,  milled 
wheel;  L,  fine  adjustment;  H,  draw  tube;  F,  objective;  M, 
stage ;  O,  mirror ;  B,  pillar ;  D,  tube,  or  body ;  S,  diaphragm. 


6 


LABORATORY   EXERCISES   IN 
ZOOLOGY 

PRELIMINARY  EXERCISES 

I.  —  USE  OF  THE  MICROSCOPE 

Materials.  —  A  compound  microscope  fitted  with  f  and  i  inch 
objectives,  glass  slides  for  mounting  objects,  wing  of  a  house  fly, 
cover  glasses ;  objects  for  mounting,  such  as  cotton  fibers,  hairs, 
blood  cell,  pond  scums,  etc. 

Directions.  —  (The  author  has  found  it  advantageous  to  set  a 
microscope  in  a  conspicuous  position  and  to  have  the  class  make  a 
diagrammatic  drawing  of  it  from  a  side  view,  afterward,  carefully 
naming  all  the  parts.) 

A.  PARTS  OF  THE  MICROSCOPE.   With  the  aid  of  Fig- 
ure 1  locate  on  the  microscope  the  following  parts :  draw 
tube,  stage,  mirror,  pillar,  large  and  small  milled  wheels, 
eyepiece,  objectives. 

B.  COARSE  ADJUSTMENT.     Place  the  microscope  on  the 
table,  with  the  pillar  next  to  the  face  and  with  the  stage 
pointing  away.    Take  hold  of  the  large  milled  wheel  on 
the  right  side,  and  turn  it  toward  the  operator.    What 
happens  to  the  tube  ?    As  the  tube  may  be  rapidly  lowered 
and  raised  by  this  wheel,  it  is  called  the  coarse  adjustment. 

C.  FINE  ADJUSTMENT.     Place  a  glass  slide  on  the  stage 
and  lower  the  f  objective  until  it  is  about  J  of  an  inch  from 
the  slip.     Put  the  head  down  until  the  eye  is  on  a  level 
with  the  stage.      Sight  across  the  slide,  and  with  the  hand 

7 


8  PRELIMINARY    EXERCISES 

turn  the  milled  wheel  on  top  of  the  pillar  to  the  right. 
What  happens  to  the  objective  ?  Does  it  move  quickly  or 
slowly  ?  The  wheel  on  top  of  the  pillar  is  called  the  fine 
adjustment.  Why  ? 

D.  TAKING  OUT  AND  PUTTING  IN  THE  EYEPIECE.    Ele- 
vate the  tube  so  that  the  objective  is  an  inch  or  more  from 
the  stage.   Grasp  the  tube  with  the  left  hand,  and  with  the 
other  hand   pull  out  the  eyepiece  by  taking  hold  of  the 
milled  ring  at  the  top.     Never  put  the  ringers  on  the  lenses, 
but  use  an  old,  soft  handkerchief  for  cleaning  them.    To 
put  the  eyepiece  in  place,  hold  the  tube  as  before,  else  the 
objective  may  be  forced  against  the  stage  and  be  broken. 

E.  TAKING  OFF  AND  PUTTING  ON  THE  OBJECTIVE/     To 
remove  the  objective,  always  elevate  the  tube.     Grasp  the 
objective  lightly  at  the  milled  ring  on  its  lower  end,  with 
the  thumb  and  forefinger  of  the  left  hand,  and  with  the 
thumb  and  forefinger  of  the  right  hand  unscrew  the  objec- 
tive at  the  milled  ring  at  its  upper  end.      In  this  way  the 
objective  will  not  be  dropped  and  broken.     To  replace 
the  objective,  reverse  the  operation.     Practice  this  until 
it  can  be  done  with  ease  and  facility. 

F.  LIGHTING  THE  OBJECT  WITH  THE  MIRROR.   Place  the 
wing  of  a  house  fly  in  a  drop  of  water  in  the  middle  of  the 
glass  slide.     Carefully  drop  a  thin  cover  glass  on  top  of 
the  wing.     Elevate  the  tube  and  place  the  object  on  the 
stage.      Then  with   the   eye  at  the  eyepiece  and  looking 
through  the  tube,  turn  the  mirror  in  different  positions. 
What  happens  ?     What  is  the  mirror  for  ?    Examine  the 
mirror  and  note  its  surfaces.      How  do  its  two  surfaces 
differ  ?     What  is  the  difference  in  effect  when  lighting  the 

1  If  microscopes  with  double  nosepieces  are  used,  this  work  is  not- 
necessary. 


USE    OF   THE    MICROSCOPE  9 

fly's  wing  with  the  concave  and  convex  sides  of  the  mirror  ? 
Which  side  throws  more  light  on  the  object  ? 

G.  DIAPHRAGM.  Note  the  circular,  revolving  disk  be- 
neath the  stage  with  its  various  sized  openings.  This  disk 
is  called  the  diaphragm.  Try  each  opening  successively, 
and  note  the  effect  on  the  wing.  Which  opening  is  best 
to  use  on  a  dark  day  ?  Which  is  best  to  use  on  a  sunny 
day  ?  It  is  best  for  the  eye  not  to  use  too  bright  light. 

H.  FOCUSING  WITH  THE  DIFFERENT  OBJECTIVES.  Using 
a  f  objective,  run  the  tube  down  until  the  bottom  of 
the  objective  is  about  \  inch  from  the  object.  With  the 
eye  at  the  eyepiece  very  slowly  lower  the  tube  until  the 
wing  comes  plainly  into  view.  The  object  is  then  said  to 
be  in  focus.  If  in  lowering  the  tube  the  wing  is  not  seen 
very  soon,  look  at  the  end  of  the  objective,  and  note  how 
close  it  is  to  the  object.  If  it  is  nearer  than  J  of  an  inch, 
elevate  the  tube  and  try  again.  Watch  closely  and  never 
run  the  objective  into  the  object.  A  f  objective  will  stand 
about  J  of  an  inch  from  the  object  when  in  focus.  A  J  will 
allow  a  piece  of  ordinary  paper  between  it  and  the  object. 

Using  the  J  objective,  run  the  tube  down  until  the  end 
almost  touches  the  object.  Then,  with  the  eye  at  the 
eyepiece,  run  the  tube  up  and  down  with  the  fine  adjust- 
ment until  the  wing  comes  into  focus.  Always  use  the 
fine  adjustment  with  the  J  objective. 

Mount  various  objects  on  slides  in  water  under  cover 
glasses.  Cotton  fibers,  hairs,  blood  cells,  pond  scums,  etc., 
will  serve  for  this  purpose.  Focus  with  both  objectives 
on  these  objects  again  and  again,  until  the  operation  of 
lighting  and  focusing  is  thoroughly  mastered. 

Reference  Book.  —  The  Microscope  and  Microscopical  Methods 
by  Simon  Henry  Gage,  Comstock  Pub.  Co.,  Ithaca,  N.Y.,  $1.50. 


10  PRELIMINARY     EXERCISES 

II.  —  THE  FUNCTIONS  OF  ORGANS 

Materials. —  A  live  locust,  a  frog,  a  chicken  leg,  a  duck's  leg, 
wing  of  a  sparrow,  fore  legs  of  a  rabbit,  a  butterfly. 

Directions.  —  (Procure  several  live  locusts  and  allow  them  to  go 
free  in  the  room  or  in  a  large  cage.) 

A.  STUDY  OF  A  LIVING  LOCUST.     Study  the  movements 
of  a  live  locust.     What  use  is  made  of  the  front  legs  ? 
What  are  the  hind  legs  used  for  ?   Note  carefully  this  dif- 
ference in  function  between  the  fore  legs  and  the  hind  legs. 
The  front  legs  are  of  most  service  in  walking,  while  the  hind 
legs  are  used  in  leaping.     Now  note  the  difference  in  size 
and  structure  between  these  pairs  of  legs.     This  comparison 
shows  us  that  a  difference  in  the  functions  of  organs  may 
be  accompanied  by  a  difference  in  the  structure  of  those 
organs. 

B.  Now  compare  the  hind  legs  of  a  locust  with  the  hind 
legs  of  a  frog.     The  frog's  hind  legs  are  also  used  as  leaping 
organs.     Is  the  relation  of  size  and  structure  between  the 
front  legs  and  hind  legs  of  these  animals  similar?    This 
comparison  shows  us  that  a  similarity  of  function  may  be 
accompanied  by  a  similarity  of  structure. 

C.  The  frog's  leg  is  also  used  for  swimming.     What 
structure  between  the  toes  fits  the  leg  for  a  swimming 
organ?    Is  such  a  structure  found  on  the  locust's  foot? 
Does  the  locust  swim  ?    It  would  seem  then,  from  this  study 
of  the  frog's  leg,  that  an  organ  is  structurally  fitted  for  the 
function  it  has  to  perform. 

D.  Study  the  leg  of  a  chicken  and  of  a  duck.     How  do 
they  differ  in  function  ?    How  do  they  differ  in  structure  ? 
Are  both  legs  especially  suited  to  the  work  they  are  called 
upon  to  perform? 


THE     CLASSIFICATION    OF    ANIMALS 


11 


Study  the  wings  of  a  sparrow,  and  compare  their  structure 
and  their  functions  with  the  structure  and  functions  of  the 
fore  legs  of  a  rabbit.  The  wings  of  a  sparrow  and  the  fore 
legs  of  a  rabbit  are  homologous  organs. 

Compare  the  mouth  parts  of  a  locust  with  those  of  a 
butterfly.  The  locust  chews  its  food,  while  the  butterfly 
sucks  its  food  (nectar)  from  flowers.  Note  the  striking 
adaptation  of  structure  to  meet  these  functions. 

This  work  may  be  carried  further,  but,  as  it  is  emphasized  through- 
out all  the  practical  work,  perhaps  further  study  here  will  not  be 
necessary. 

III.  —  THE  CLASSIFICATION  OF  ANIMALS 

Materials.  —  Several  specimens  of  tobacco  worm  and  tomato 
worm  moths,  members  of  the  hawk-moth  family,  beetles,  butter- 
flies, flies,  bugs,  etc. 

Directions.  —  During  the  summer  collect  several  speci- 
mens of  the  tobacco  and  tomato  worm  moths.  If  the 
moths  l  cannot  be  obtained  readily,  find  the  larvae  and  rear 
them  in  cages  (see  Appendix).  By  rearin'g  the  moths 
more  perfect  specimens  may  be  obtained.  Also  collect  other 
members  of  the  Hawk-moth  family,  the  Pandora  Sphinx,2 
the  Lesser  Vine  Sphinx,2  etc.,  and  some  beetles,  butterflies, 
flies,  and  bugs.  If  it  is  more  convenient  to  obtain  butter- 
flies, collect  different  species  of  the  cabbage  butterflies.3 

A.  Compare  any  two  individuals  of  the  tomato  moths. 
Note  the  shape  of  the  fore  and  the  hind  wings.  Note  the 
colors  of  the  wings  of  each  moth,  and  compare.  Note  the 

1  See  the  "Moth  Book"  by  W.  J.  Holland,  Plate  IV,  Figs.  1  and  2. 

2  Ibid.,  Plate  III,  Figs.  6  and  2. 

3  See  "How  to  Know  the  Butterflies"  by  Comstock,  Plates  XIII 
and  XIV. 


12  PRELIMINARY  '  EXERCISES 

markings  on  the  abdomens,  and  compare.  Note  the  size 
of  the  wings,  and  compare.  As  a  result  of  these  compari- 
sons, note  that  the  wings  and  abdomens  of  these  moths 
are  alike  in  size,  shape,  and  color.  Evidently,  they  are  of 
the  same  kind,  —  simply  two  individuals  of  the  same  kind 
of  insect.  There  are  many  other  individual  tomato  moths 
in  the  world,  all  of  which  are  of  the  same  kind  and  are  known 
as  a  species. 

Examine  two  of  the  tobacco  moths  in  the  same  way,  and 
compare.  Here,  again,  we  find  several  individuals  so  nearly 
alike  that  we  consider  them  the  same  kind,  or  species. 

B.  Now  compare  a  tobacco  moth  and  a  tomato  moth. 
They  are  not  alike  and  are  not  of  the  same  species,  for  they 
differ  in  the  colors  of  the  wings  and  the  markings  of  the 
abdomens.  Yet  they  have  similar  antenna?,  wings  of 
nearly  the  same  shape,  and  abdomens  alike  in  size  and  shape. 
Clearly,  they  are  very  closely  related  species  and  may  be 
assembled  in  one  group.  Such  a  group,  composed  of  several 
very  closely  related  species,  is  known  as  a  genus. 

A  genus  is  given  a  single  name  taken  from  the  Greek  or 
the  Latin  language.  The  genus  containing  the  tomato  and 
tobacco  moths  is  known  as  Protoparce.  There  are  other 
moths  that  belong  to  this  genus,  and  they  are  all  known 
under  the  name  of  Protoparce.  But,  since  the  tobacco  and 
tomato  moths  are  different  species,  they  must  have  differ- 
ent names  in  order  that  we  may  be  able  to  designate  them. 
Therefore,  the  tomato  moth  is  called  Protoparce  sexta  and 
the  tobacco  moth  is  called  Protoparce  quinquemaculatus. 
In  these  names  the  word  Protoparce  indicates  the  genus 
to  which  these  moths  belong,  while  the  words  sexta  and 
quinquemaculatus  indicate  the  respective  species  to  which 
they  belong.  That  is,  the  scientific  name  of  every  animal 


THE    CLASSIFICATION    OF    ANIMALS  13 

consists  of  two  words,  the  first  of  which  is  the  name  of  the 
genus  to  which  it  belongs,  while  the  second  is  the  name  of 
the  species  to  which  the  animal  belongs. 

C.  Examine  the  Pandora  Sphinx  and  the  Lesser  Vine 
Sphinx,  —  other  hawk  moths  will  do  quite  as  well.    Note 
that  these  are  quite  different  from  the  tobacco  and  tomato 
moths  in  the  colors  and  markings  of  the  wings  and  abdo- 
mens.    Indeed,  the  Pandora  and  Lesser  Vine  Sphinxes  are 
so  unlike  the  tobacco  and*  tomato  moths  that  the  former 
are  placed  in  an  entirely  different  genus,  namely,  Pholus. 
Yet  all  of  these  moths  have  a  general  similarity.    They 
all  have  long,  narrow,  graceful  front  wings  and  small  hind 
wings.     Their  abdomens  are  comparatively  large,  and  they 
fly  at  twilight  or  at  night.     They  all  have  long  probosces 
with  which  they  suck  the  nectar  from  the  flowers  of  honey- 
suckles and  other  plants.     Therefore,  these  two  genera  of 
moths,  together  with  other  genera  of  like  moths,  constitute 
a  family  known  as  the  hawk-moth  family  (Sphingidse) . 

D.  Compare  the  hawk  moths  with   other  moths  and 
with  butterflies.      Note  that  when  handled  a  fine  dust- 
like  substance  is  rubbed  from  the  wings  and  is  left  cling- 
ing to  the  fingers.      Examine  this  dust  under  the  micro- 
scope.    It  will  be  seen  to  consist  of  minute  scales  of  various 
forms.     With  very  few  exceptions,  the  wings  of  all  moths 
and  butterflies  are  clothed  with  fine  scales,  and  are  conse- 
quently similar  in  this  respect.     On  account  of  this  simi- 
larity  butterflies   and  moths  are  all  assembled  together 
in  a  large  group  known  as  an  order  (Lepidoptera) . 

E.  To  carry  our  classification  further,  many  more  insects 
of  different  kinds  must  be  compared.     It  will  be  found 
in  such  comparison  that  they  all  have  six  legs  and  that  their 
bodies  consist  of  three  great  divisions,  —  head,  thorax,  and 


14  PRELIMINARY     EXERCISES 

abdomen.  Therefore,  all  insects  fall  into  one  great  group 
known  as  a  class  (Hexapoda,  or  Insecta).  To  go  further 
and  compare  insects  with  crayfish,  lobsters,  spiders,  sow 
bugs,  etc.,  we  should  find  that  all  of  these  animals  have 
segmented  legs  and  segmented  bodies.  Therefore,  on  account 
of  these  similarities,  they  are  all  assembled  in  one  great 
group  known  as  a  branch  ( Arthropoda) . 

If  time  is  available,  no  better  scheme  of  improving  it 
could  be  devised  than  by  devoting  a  few  exercises  to  the 
classifying  of  a  few  common  insects.  For  example,  collect 
several  specimens  of  our  common  insects  representing  the 
orders  of  locusts,  bugs,  flies,  beetles,  bees,  and  butterflies. 
Make  a  careful  study  of  the  leading  characteristics  —  the 
similarities  and  differences  —  of  the  individuals  until  the 
insects  of  like  characteristics  can  be  grouped  by  themselves. 
Name  the  groups  (orders).  Select  some  cabbage  butter- 
flies and  some  swallow-tail  butterflies.  Note  the  differ- 
ences and  similarities  and  separate  them  into  groups  con- 
taining like  individuals/  Name  the  groups  (genera). 
Finally,  select  some  individual  swallow-tail  butterflies  and 
separate  them  into  species. 

IV.  —  PLANT  CELLS 

Materials.  —  Pond  scums,  glass  jars,  melon  vine,  moss,  glass 
slides,  cover  glasses,  compound  microscope. 

Directions.  —  Collect  some  pond  scums  from  different 
sources  and  keep  them  in  glass  jars,  changing  the  water 
now  and  then  to  prevent  it  from  becoming  too  stagnant. 
Spirogyra  is  a  very  common  species  of  pond  scum.  It 
may  be  recognized  from  the  green,  spiral  bands  inside  the 
long,  slender  threads. 


PLANT    CELLS  15 

Find  a  melon  vine,  or,  some  time  before  it  is  needed,  plant 
some  seeds  of  this  vegetable  in  a  pot  and  allow  the  plants 
to  grow  a  foot  or  more  in  length.  Collect  a  quantity  of  a 
moss  that  has  thin,  flat  leaves,  and  keep  it  in  a  moist  jar 
until  wanted. 

A.  Mount  a  bit  of  the  pond  scum  in  water  on  a  glass  slide 
and  cover  with  a  cover  glass.     Examine  with  the  low  power 
(§)  objective. 

What  is  the  color  of  the  plant  ?  Of  what  does  the  plant,  as 
a  whole,  consist  ?  What  are  the  structural  units  of  a  single 
thread  ?  What  is  the  shape  of  each  cell  ?  Note  the  spiral 
band  in  each  cell.  Are  the  cells  longer  than  they  are  wide  ? 

Make  drawings  showing  the  threads  and  the  cells.  Make 
notes  on  the  color,  appearance,  and  habitat  of  the  plant. 

B.  Mount  a  leaf  of  the  moss.    Note  the  shape  of  the  leaf 
and  the  midrib.     Note  that  the  leaf  is  made  up  of  cells. 
Note  that  the  cells  are  of  various  sizes  and  shapes.     What 
is  contained  within  them  ?     Do  they  possess  walls  ? 

Make  a  drawing  of  the  whole  leaf  and  then  of  a  half 
dozen  cells  much  enlarged. 

C.  Examine  the  melon  vine,  and  note  the  fuzzy  ap- 
pearance   of    the    stems.     What    causes    it?    Carefully 
scrape  off  some  of  the  hairs  with  a  sharp  scalpel  or  knife 
and  mount  them  on  a  glass  slide  in  water.     Examine  with 
the  low-power  objective,  and  note  the  shape  and  structure 
of  each  hair.     What  is  the  shape  of  each  cell  ?    Note  that 
the  cells  are  joined  end  to  end. 

Make  a  drawing  of  a  hair  showing  its  structure. 

With  the  high-power  objective  watch  closely  for  some 
length  of  time  a  single  cell.  Is  the  wall  of  the  cell  opaque 
or  transparent?  What  is  inside  of  the  cell?  Note  a 
light,  circular  spot,  the  nucleus,  usually  at  one  side  of  the 


16  PRELIMINARY     EXERCISES 

cell.  Look  carefully  for  the  fine  threads  of  protoplasm 
running  from  the  nucleus  to  different  parts  of  the  cell. 
Is  there  any  movement  in  these  threads?  (N.B.  —  It 
will  take  close,  careful  observation  to  determine  this  point.) 

Make  a  drawing  showing  the  cell  and  its  nucleus  and 
streams  of  protoplasm. 

In  conclusion  it  will  be  noted  that  all  the  plant  cells 
examined  possess  walls.  This  is  true  of  most  plant  cells, 
although  there  are  exceptions.  Note  that  each  cell  con- 
tained protoplasm  and  a  nucleus,  although  these  structures 
could  not  be  made  out  easily,  in  the  cells  of  the  pond  scum 
and  moss  leaf.  Finally,  note  that  the  protoplasm  had  the 
power  of  movement. 

V.  —  ANIMAL  CELLS 

Materials.  —  Scalpel  or  ivory  knife,  glass  slides  and  cover 
glasses,  compound  microscope ;  amoebae ;  one  per  cent  acetic  acid ; 
paramecia,  peach-tree  gum  or  cotton  fiber;  vorticellae. 

Directions.  —  (Amcebse  are  sometimes  difficult  to  obtain  in  suf- 
ficient numbers  for  a  whole  class ;  but  epithelial  cells  may  be  ob- 
tained, simply  by  scraping  the  inside  of  the  cheeks  with  a  sterilized 
scalpel,  or  ivory  knife.) 

A.  AN  EPITHELIAL  CELL.    Place  the  substance  obtained 
from  the  mouth  upon  a  slide,  cover  with  cover  glass,  and 
examine  with  low-power  objective.     Are  there  any   cells 
in  the  material  ?    What  are  the  shapes  of  the  cells  ?    Note 
the  nucleus  in  any  one.     Note  the  granular  protoplasm 
and  the  wall  bounding  the  cell.     Draw  some  of  these  cells. 

B.  AMCEBA.     (If  possible,  obtain  a  few  amoeba.     They  live  in 
the   ooze  and  slime   on  leaves,   sticks,   etc.,   in   standing  water. 
Collect  this  material  from  different  places,  and  allow  it  to  stand 


ANIMAL    CELLS  17 

in  shallow  dishes  for  several  weeks,  being  careful  not  to  allow  all 
the  water  to  evaporate.  Cultures  of  these  materials  should  be 
started  in  the  spring  for  work  in  the  autumn.) 

Mount  on  slides  bits  of  the  material  from  the  different 
dishes  and  search  carefully  for  opalescent  or  transparent 
spots  that  are  constantly  changing  position.  This  is  often 
a  little  tedious,  and  needs  to  be  persisted  in  to  be  success- 
ful. 

Having  found  the  animal,  note  its  movements.  Does 
it  always  ntove  in  one  direction  ?  Write  a  description  of 
the  various  movements  of  the  amoeba.  Judging  from  the 
directions  in  which  the  amoeba  moves,  does  it  have  an 
anterior  and  posterior  end?  Of  what  is  the  body  of  the 
amoeba  composed  ?  Is  the  body  clear  or  granular  ?  Find 
an  oval,  transparent  organ,  the  nucleus,  within  the  body 
mass.  Is  the  amreba  composed  of  one  or  more  than  one 
cell  ?  Is  the  body  inclosed  by  walls  ?  What,  then,  is  the 
great  difference  between  this  animal  cell  and  the  plant  cells 
already  examined  ?  From  what  part  of  the  body  are  the 
streams  of  protoplasm  sent  out?  Find  the  particles  of 
food  surrounded  by  water.  These  are  known  as  the  food 
vacuoles.  How  does  an  amoeba  obtain  its  food  ?  See  text, 
page  15.  How  does  it  breathe?  Note  the  contractile  vac- 
uole.  This  is  a  globule  of  clear  liquid  which  forms  near 
the  outside  of  the  animal  and  discharges  into  the  surround- 
ing water.  How  often  does  it  pulsate  ? 

The  contractile  vacuole  is  an  organ  of  excretion  by  which 
the  waste  products  are  thrown  out  of  the  body. 

To  see  the  nucleus  in  this  animal  and  the  following 
one-celled  forms,  they  should  be  killed  by  a  one  per  cent 
solution  of  acetic  acid,  when  the  nucleus  will  become  visible 
in  the  dead  bodies. 

HERRICK  LAB.  EX. 2 


18  PRELIMINARY     EXERCISES 

Note  the  clear  layer  of  protoplasm  around  the  outside  of 
the  body.  This  is  the  ectoplasm.  TJie  granular  inner  pro- 
toplasm is  called  the  endoplasm.  Note  the  flow  of  granules 
along  the  pseudopodia.  If  the  animal  comes  in  contact 
with  a  particle  of  sand,  note  its  behavior.  Does  the  amoeba 
possess  sensation,  judging  from  its  action  when  touching 
the  sand? 

Make  drawings  of  the  amceba  in  two  different  positions. 

C.  PARAMECIUM.  (These  animals  may  be  obtained  by  plac- 
ing a  handful  of  hay  in  a  jar  of  pond  water  together  with  some  de- 
caying sticks  and  leaves.  Place  the  jar  in  a  warm  place,  and  in  a 
few  weeks  there  should  be  an  abundance  of  paramecia  just  beneath 
the  scum  which  will  appear  on  top  of  the  water.) 

Mount  some  of  the  material  on  a  slide  in  water.  Note 
the  paramecia  moving  rapidly  in  the  field.  If  they  move 
too  rapidly  for  study,  they  may  be  entangled  in  fibers  of 
cotton  placed  beneath  the  cover  glass.  A  thin  solution 
of  peach-tree  gum,  made  by  melting  the  gum  in  water, 
makes  a  very  good  mounting  medium.  The  gum  solution 
will  retard  their  movements  sufficiently  for  study. 

Note  the  shape  of  the  body.  Note  that  the  body  is 
inclosed  by  a  very  thin,  transparent  cuticle.  Did  the 
amoeba  have  such  a  cuticle  ?  Is  the  body  divided  into  com- 
partments by  cross  partitions  ?  Is  this  a  one-celled  animal  ? 
Note  that  the  body  is  covered  by  rows  of  cilia.  If  the  para- 
mecium  is  killed  by  a  one  per  cent  solution  of  acetic  acid,  the 
cilia  will  show  more  plainly.  Where  are  the  longest  cilia  ? 

Note  on  one  side  of  the  body  a  groove,  —  the  oral  groove. 
From  this  a  throat  leads  into  the  interior  of  the  body.  The 
mouth  is  at  the  bottom  of  this  throat.  The  nucleus  may 
be  seen  in  the  dead  animal. 

Mount  some  more  living  ones  and  observe  the  movements 


ANIMAL    CELLS  19 

of  the  animals.  Do  they  move  as  though  they  had  anterior 
and  posterior  ends  ?  Do  they  move  in  straight  lines  ?  In 
moving,  is  the  same  side  of  the  body  kept  uppermost  all 
the  time?  It  will  be  noted  that  the  body  revolves  now 
and  then.  The  paramecium  is  unsymmetrical,  and  if  it 
did  not  revolve  it  would  travel  in  a  circle. 

Does  the  paramecium  seem  more  complex  than  the 
amoeba  ? 

Make  a  drawing  showing  all  the  structures  noted  above. 

D.  VORTICELLA.  (Ordinarily  this  may  be  obtained  by  gath- 
ering leaves,  sticks,  and  pond  scum  from  fresh-water  ponds  and 
pools  and  allowing  them  to  stand  for  a  few  days  in  a  warm  place. 
Very  often  they  may  be  found  in  the  material  at  once.  Sometimes 
colonies  of  certain  species  may  be  seen  with  the  naked  eye,  as  a 
whitish  mold,  along  the  surface  of  a  leaf  or  stick.  Jar  the  dish  and 
note  the  sudden  contraction  of  the  whole  mass.) 

Mount  some  of  the  vorticellse.  Note  the  sudden  dis- 
appearance of  one  and  then  its  slow  reappearance  into  the 
field  of  the  microscope.  Is  the  animal  attached  to  any- 
thing? If  so,  how?  Note  the  transparent  sheath  of  this 
stem  and  the  solid  rod  within.  What  happens  to  the  stem 
when  the  animal  contracts?  Note  the  action  of  the  stem 
when  the  animal  pushes  out  into  the  field  again.  When 
the  vorticella  contracts  what  shape  does  the  body  assume  ? 
What  is  the  shape  of  the  body  when  the  animal  is  fully 
expanded  ?  What  is  seen  around  the  edge  of  the  inverted 
bell-like  body  ?  Do  these  cilia  move  ?  Note  the  deep  oral 
groove,  bordered  by  cilia  that  extends  from  the  edge  of  the 
bell  into  the  body.  The  mouth  is  borne  at  the  lower  end 
of  this  groove.  Note  the  currents  of  water  that  are  being 
directed  toward  the  oral  groove  by  the  cilia.  What  are 
these  currents  for  ? 


20  PRELIMINARY     EXERCISES 

Note  that  the  body  is  inclosed  by  a  thin  cuticle  like  that 
of  the  paramecium.  Note  the  crescent-shaped  nucleus. 

Make  written  descriptions  of  the  movements  of  the  vor- 
ticella. 

Make  a  drawing  of  the  body. 

E.  TOPICS  FOR  FURTHER  STUDY.  Sum  up  the  char- 
acteristics of  all  these  animals.  Write  out  a  comparison 
of  the  manner  in  which  the  different  forms  obtain  and  digest 
food,  move,  breathe,  and  reproduce.  Define  a  living  ani- 
mal cell  from  your  observation  of  these  forms. 


STUDIES   OF  ANIMAL  TYPES 
VI.  —  A  SIMPLE  MARINE  SPONGE  (Grantia) 

Materials.  —  Specimens  of  Grantia  preserved  in  formalin  or 
alcohol,  watch  glasses,  scalpels  or  razors,  caustic  soda,  test  tubes, 
glass  slides,  cover  glasses,  compound  microscope. 

These  sponges  occur  in  the  sea  along  the  Atlantic  and  Pacific 
coasts,  and  may  be  obtained  from  dealers  in  zoological  specimens. 

Directions.  —  (Place  the  individual  sponges  in  water  in  watch 
glasses  or  small  shallow  dishes.) 

A.  EXTERNAL  FEATURES.    Note  the  shape  of  the  body. 
Note  the  collar  of  long,  transparent  spicules  around  the 
free  end  of  the  sponge.    In  nature  the  other  end  is  attached 
to  some  object  in  the  sea.    Note  the  smaller  sponges  at- 
tached to  the  bases  of  larger  ones  in  some  cases.    These  are 
produced  by  the  process  of  budding. 

Note  that  the  collar  of  long  spicules  surround  an  opening, 
the  osculum,  or  mouth.  This  osculum  is  also  called  the 
exhalent  opening,  because  the  water  flows  out  of  the  body 
through  it.  Observe  the  small  spicules  covering  the  whole 
body.  Can  the  openings  of  minute  pores  be  seen  on  the 
sides  of  the  body  ? 

Make  a  drawing  of  the  animal. 

B.  INTERNAL  FEATURES.    With   a  very  sharp   scalpel 
or  old  razor  cut  a  dry  specimen  in  halves,  lengthwise. 
Is" the  body  solid  or  hollow  ?    With  the  low  power  objective 
examine  the  sides  of  the  body  cavity  and  note  the  minute 
openings  in  them  everywhere.     These  are  the  openings  of 

21 


22  STUDIES    OF   ANIMAL   TYPES 

a  system  of  radial  canals  that  run  nearly  through  the  walls 
of  the  body,  but  end  blindly  just  before  reaching  the  out- 
side. Make  a  very  thin,  longitudinal  section  with  a  razor 
and  examine  with  the  microscope.  Note  these  radial  canals 
and  also  a  set  of  parallel  canals  that  begin  at  the  outside 
of  the  body  and  end  blindly  just  before  reaching  the 
body  cavity.  The  radial  and  inhalent  canals  communicate 
with  each  other  by  fine  openings  through  their  adjoining 
walls. 

Draw  one  half  of  the  sponge  (enlarged)  to  show  the 
body  cavity  and  the  radial  canals. 

Make  a  very  thin  cross  section  of  a  dry  sponge.  Note 
the  round  opening  in  the  center  of  the  section.  What  is 
this  ?  Note  the  two  sets  of  canals  mentioned  above.  Note 
the  arrangement  of  'the  spicules  in  the  walls  of  these 
canals. 

Boil  a  small  piece  of  the  sponge  for  a  short  time  in  caus- 
tic soda,  in  a  test  tube.  The  spicules  will  separate  from 
the  tissues  and  fall  to  the  bottom.  Mount  some  of  them  on 
a  slide.  At  least  two  kinds  will  be  found,  the  tri-radiate 
and  the  needle-shaped.  The  tri-radiate  spicules,  will, 
for  the  most  part,  have  the  "prongs  running  off  at  equal 
angles  of  120°  from  each  other.  Occasionally  some  will 
be  found  in  which  the  prongs  form  right  angles.  In  this 
case  the  spicules  are  T-shaped. 

Make  drawings  of  the  different  kinds  of  spicules. 

C.  TOPICS  FOR  FURTHER  STUDY.  Sum  up  the  leading 
characteristics  of  a  simple  sponge.  To  what  branch  does 
it  belong  ?  Compare  it  with  an  amoeba.  Discuss  its  man- 
ner of  obtaining  food.  How  does  it  reproduce?  How 
does  it  respire  ?  Where  is  it  found  ?  Note  that  it  is  a 
multicellular  animal,  but  stands  next  'to  the  Protozoa. 


THE    FRESH-WATER    HYDRA  23 


VII.  —  THE   FRESH- WATER  HYDRA 

Materials.  —  Hydras  in  glass  jars,  pipette,  watch  glasses,  hand 
lens  or  low-power  objective,  glass  slides  and  cover  glasses,  com- 
pound microscope. 

Directions.  —  (The  fresh-water  hydra  is  found  nearly  everywhere 
in  ponds,  ditches,  and  pools,  attached  to  sticks,  leaves,  etc.  It  is 
often  found  among  duck  weed.  We  have  often  found  the  green 
hydra  in  ditches  among  spirogyra.  Collect  some  of  these  materials 
and  place  them  in  glass  jars  in  a  warm  room  some  days  before  needed. 
The  hydras,  if  present,  will  be  seen  attached  to  the  sides  of  the  jar.) 

A.  STUDY  OF  LIVING  HYDRA.    Observe  them  in  the  jar. 
Are  they  free  or  attached?    How  do  they  differ  from 
paramecia  in  regard  to  their  movements?    What  is  the 
shape  of  the  body  ?    What  is  on  the  free  end  of  the  body  ? 
How  many  of  these  tentacles  are  there?    Do  they  have 
the  power  of  movement  ?    Tap  the  jar  and  note  the  effect. 

What  is  the  color  of  the  hydra  ?  (There  are  two  species, 
the  green  hydra  and  the  brown  hydra.)  Is  the  free  end  of 
the  hydra  held  up  or  down?  If  neither,  how  is  it  held? 
Note  the  gentle  swaying  of  the  body  and  tentacles.  When 
the  hydra  contracts,  what  shape  does  the  body  assume? 
Also  note  the  appearance  of  the  tentacles  when  they  contract. 

B.  EXTERNAL  FEATURES.     By  means  of  a  pipette  or 
glass  tube,  remove  one  of  the  hydras  and  place  it  in  water 
in  a  watch  glass. 

With  a  hand  lens  or  low  objective,  note  the  long,  cylin- 
drical body.  Note  the  tentacles  and  their  number.  Note 
the  irregularities  or  small  knobs  all  over  the  distal  end  of 
the  body  and  the  tentacles.  Tap  the  glass  and  note  effect. 

Get  one  in  position  to  note  the  mouth  between  the  bases 
of  the  tentacles.  The  attached  end  of  the  body  is  called 


24  STUDIES    OF   ANIMAL   TYPES 

the  foot.  It  is  an  adhesive  disk  wjiich  gives  out  a  sticky 
secretion  for  attachment  to  submerged  objects. 

Make  a  drawing  of  the  body  to  show  its  shape. 

C.  STRUCTURE  OF  THE  BODY.  Mount  the  living  hydra 
in  a  drop  of  water  beneath  a  cover  glass,  with  a  hair  or 
small  strip  of  paper  on  either  side,  to  prevent  the  cover 
glass  from  crushing  it. 

Examine  with  both  objectives.  Note  that  the  body  is 
simply  a  tube.  The  large  hollow  running  lengthwise  of 
the  body  is  the  body  cavity  (gastrovascular  cavity). 
This  is  the  digestive  and  circulatory  cavity  in  one,  for  the 
hydra  has  no  alimentary  canal  and  blood  vessels.  The 
food,  which  consists  of  small  crustaceans  and  other  minute 
animals,  is  passed  into  the  mouth  by  the  tentacles.  The 
cells  lining  the  body  cavity  secrete  a  digestive  fluid  which 
acts  upon  the  food,  preparing  it  for  assimilation.  The 
flagella,  which  project  from  the  cells  lining  the  body  cavity, 
create  currents  that  carry  the  food  to  all  parts  of  the  body. 

With  the  high  objective  note  the  two  layers  in  the  body 
walls.  There  is  an  outer  layer,  the  ectoderm,  and  an  inner 
layer,  the  endoderm.  Compare  the  shape  of  the  cells  of 
the  ectoderm  and  of  the  endoderm.  How  do  they  differ? 
If  the  hydra  is  a  green  one,  note  the  green  bodies  (Algal 
cells)  embedded  among  the  cells  of  the  endoderm. 

Note  the  prominent,  rounded,  oval  cells  in  the  ectoderm 
of  the  tentacles  and  the  distal  portion  of  the  body.  These 
are  the  stinging  thread  cells.  If  necessary,  crush  a  tentacle, 
in  order  to  get  a  good  view  of  one  of  these  cells.  Note  the 
fine  thread  coiled  within  each  cell. 

Draw  a  stinging  thread  cell. 

Make  a  diagrammatic  drawing  of  the  body  showing  its 
general  structure. 


A    CAMPANULARIAN    HYDROID  25 

Note  that  some  individuals  have  small  hydras  attached 
to  the  sides  of  their  bodies.  Hydras  reproduce  by  budding 
(see  text,  page  49). 

D.  TOPICS  FOR  FURTHER  STUDY.  Give  the  leading 
characteristics  of  the  hydra.  Discuss  its  manner  of  obtain- 
ing and  digesting  food,  its  reproduction,  and  movement. 
Compare  it  with  a  sea  anemone,  coral  polyp,  and  jellyfish. 
Fix  firmly  hi  mind  the  position  of  the  hydra  and  its  rela- 
tives in  the  animal  kingdom. 

VIII.  —  A  CAMPANULARIAN  HYDROID 

Materials.  —  Campanularian  hydroid,  glass  slides,  cover  glasses, 
compound  microscope. 

Directions.  —  (This  ccelenterate  lives  in  the  sea  attached  to 
rocks,  seaweed,  etc.,  and  may  be  obtained  from  any  of  the  dealers 
mentioned  on  page  110.) 

Mount  some  of  it  in  water  on  a  glass  slide.  Note  with 
the  naked  eye  its  resemblance  to  a  plant.  What  color  is  it  ? 
What  is  the  general  form  of  the  animal?  The  stem  with 
its  branches  is  called  the  hydrocaulus.  Note  the  horizon- 
tal, threadlike  stems  running  along  the  surface  of  the  sea- 
weed to  which  the  animal  is  attached.  Note  that  the  hy- 
drocaulus is  attached  to  these  stems,  which  are  called  the 
hydrorhiza.  What  surrounds  all  the  stems  and  branches? 
This  transparent  sheath  is  called  the  perisarc.  Inside  the 
perisarc  note  the  dark  rod,  or  axis.  This  is  the  ccenosarc. 
Note  that  it  runs  into  all  the  branches  and  connects  with 
the  zooids. 

It  will  be  noted  that  there  are  two  kinds  of  zooids,  the 
nutritive  and  the  reproductive.  The  nutritive  are  situated 
at  the  ends  of  the  side  branches.  Note  that  the  perisarc 


26  STUDIES    OF   ANIMAL  TYPES 

is  expanded  at  the  ends  of  the  branches  into  cuplike  forms 
in  which  the  nutritive  zooids  sit.  Are  all  the  nutritive 
zooids  expanded  ?  They  can  contract  and  withdraw  into 
the  cuplike  ends  of  the  branches,  and,  no  doubt,  some  will 
be  foungi  in  those  positions.  Note  the  immature  zooids 
at  the  ends  of  some  of  the  branches. 

Look  along  the  hydrorhiza,  near  the  base  of  the  hydro- 
caulus,  and  in  the  axils  of  the  side  branches,  for  smooth, 
club-shaped  bodies.  Note  that  they  resemble  a  large  cap- 
sule and  contain  many  globular  bodies.  These  are  the 
reproductive  zooids.  They  contain  the  medusae  buds.  After 
a  time  the  capsule  (gonotheca)  breaks  open,  and  the  me- 
dusa buds  escape,  and  develop  into  umbrella-shaped 
medusae,  or,  as  they  are  often  called,  jellyfish.  After 
swimming  about  for  a  time  the  medusae  produce  eggs  that 
in  turn  develop  into  the  plantlike  structure  which  we  are 
now  studying. 

Make  a  drawing  showing  all  the  points  mentioned. 

IX.  —  THE  STARFISH 

Materials.  —  Specimens  of  starfish  preserved  in  formalin  or 
alcohol,  also  some  living  specimens,  if  possible,  dissecting  instru- 
ments, fine-pointed  syringe,  carmine,  brittle  stars  and  sea  urchins 
for  comparison. 

Directions.  —  (Those  living  inland  can  obtain  starfish  from 
a  dealer  in  supplies  of  that  kind.  See  page  110.  Such  specimens 
will  be  preserved  in  alcohol  or  formalin.) 

A.  EXTERNAL  FEATURES.  Note  the  color  of  the  body 
above.  In  one  common  species  the  bluish  ones  are  the 
females  while  the  lighter  colored  ones  are  the  males.  Note 
that  the  body  and  rays  are  more  or  less  flexible,  yet  hard. 


THE    STARFISH  27 

The  body  is  composed  of  calcareous  plates,  or  ossicles, 
joined  to  one  another  by  a  soft,  flexible  membrane.  Note 
the  many  harsh  spines  all  over  the  body,  both  above  and 
below.  This  array  of  spines  is  a  characteristic  of  the  branch, 
Echinodermata,  although  it  is  not  constant.  Note  that  the 
body  consists  of  a  central  disk  from  which  radiate  five 
arms.  This  radial  symmetry  is  universal  throughout  the 
Echinodermata.  Are  the  spines  ever  in  rows  on  the  arms  ? 
What  is  the  shape  of  each  arm  ?  Does  every  specimen  have 
five  arms  ?  If  not,  find  a  possible  explanation.  The  lower 
surface  of  the  body  upon  which  the  mouth  is  situated  is 
called  the  oral  surface.  The  upper  surface  is  called  the 
aboral  surface,  i.e.  the  surface  away  from  the  mouth. 

Note  on  the  aboral  surface,  between  the  bases  of  two  arms, 
a  small,  circular  plate,  marked  with  undulating  lines. 
This  is  the  madreporite.  It  is  the  cover  to  the  stone  canal. 
Find  the  small,  soft,  filiform  processes  that  project  on  Hie 
aboral  surface  between  the  calcareous  plates.  These  are 
the  branchice. 

Make  a  drawing  of  the  aboral  surface,  showing  as  many 
of  these  structures  as  possible. 

On  the  oral  surface,  in  the  center,  note  the  mouth. 
Note  the  spines  projecting  over  it.  Cut  these  away  and 
find  the  opening  of  the  mouth.  Is  it  circular  or  pentagonal  ? 
Note  that  a-  groove  runs  along  the  middle  of  each  arm. 
These  are  the  ambulacral  grooves.  Each  one  of  these 
grooves  is  bordered  by  two  or  three  rows  of  movable 
calcareous  spines. 

Note  on  the  sides  of  each  groove  two  rows  of  soft  white 
projections,  the  tube  feet.  The  areas  occupied  by  the  tube 
feet  are  the  ambulacral  areas. 

Make  a  drawing  showing  these  structures. 


28  STUDIES   OF  ANIMAL  TYPES 

B.  INTERNAL  FEATURES.  Turn  the  animal  on  the  oral 
side  and  cut  off  the  tip  of  one  ray.  Note  that  the  space  in- 
side is  taken  up  by  two  soft  brown  organs.  With  a  pair 
of  scissors,  cut  carefully  along  each  side  of  the  arm  to  the 
disk.  Lift  up  the  aboral  wall,  and  gently  cut  the  membrane 
which  holds  the  soft  brown  organs  to  the  wall.  They  will 
then  fall  down  and  lie  in  the  arm . ,  Serve  each-ray -  in-the 
same  way.  Then  carefully  cut  away  the  aboral  wall  of  the 
central  disk.  ¥igttre-44--(text)  shows-  a  starfish  treated~4n 
this— manner.  Note  that  there  are  two  branches  of  the 
soft  brown  organs  in  each  arm.  These  organs  are  the 
pyloric  cceca,  or  " .livers/ '  as  they  are  often  called.  Note  that 
each  pair  of  branches  is  connected  by  a  small  tube  with 
a  large  membranous  pouch  over  the  mouth.  This  pouch 
is  the  stomach.  The  stomach  is  often  found  protruding 
from  the  mouth.  Turn  to  the  text  and  find  out  how  the 
starfish  procures-its  food.  Note  the  short  gullet  leading 
from  the  mouth  to  the  stomach.  There  is  also  a  short 
intestine  leading  from  the  stomach  to  an  opening  through 
the  aboral  wall.  Ta  the  intestine  is  attached  a  small  con- 
voluted, branched  tube,  the  intestinal  ccecum.  Trace  .the 
intestine  to  its  outlet  and  find  the  intestinal  ca3cum. 

Remove  the  pyloric  caeca.  Note  on  the  floor  of  tharay 
two  double  rows  of  white  globular  sacs.  These  are  the 
ampullce.  *  They  are  connected  with  the  tube  feet  and  are 
filled  with  a  watery  fluid  which,  when  the  ampullae  are  con- 
tracted, is  forced  into  the  tube  feet,  thus  lengthening  and 
expanding  these  organs  of  locomotion.  There  are  two 
glandular,  reproductive  organs  in  each  arm.  They  lie  at 
the  very  base  of  the  arm  where  the  latter  joins  the  disk. 
In  some  specimens,  depending  upon  the  maturity  of  the 
animal,  these  organs  reach  almost  to  the  tip  of  the  ray, 


THE    STARFISH  29 

while  in  younger  individuals  they  are  not  more  than  half 
an  inch  long.    HW  f^^^Ots   ^uft  ORfcrftMS  faL  A    H  ? 
Make  a  drawing  ohowing  thcGa-s 


The  nervous  system.  —  Part  the  rows  of  tube  f  eek  along 
th&^middle  of  each  ray  and  note  a  yellowish,  white  ridge, 
the  nerve  of  the  ray.  Trace  this  nerve  to  the  mouth  and 
find  the  nerve  ring  that  surrounds  the  mouth.  Again,  trace 
the  nerve  of  the  ray  to  its  outer  extremity  and  find  a  red 
spot,  the  eye-spot.  The  eye-spot  is  situated  at  the  base  of 
a  so-called  tentacle  which  resembles  a  tube  foot,  but  is 
smaller  and  has  no  sucking  disk. 

Diagram  the  nervous  system. 

The  water-vascular  system.  —  If  a  fresh  specimen  can  be 
obtained,  cut  off  the  tip  of  a  ray.  Note  the  small  tube  that 
runs  along  the  floor  of  the  ray.  With  a  fine  pointed  syringe, 
inject  some  carmine  into  this  tube.  The  vessels  connected 
with  it  can  then  be  easily  traced.  Many  of  them  can  be 
made  out  with  an  alcoholic  specimen  not  injected.  Note 
that  just  inside  the  mouth,  around  the  gullet,  is  a  five-sided 
canal,  the  ring  canal.  A  hard  tube  runs  from  this  to  the 
madreporic  plate,  called  the  stone  canal,  because  its  walls 
contain  a  series  of  calcareous  rings.  From  the  ring  canal 
radiate  five  canals,  one  for  each  arm.  These  are  the  radial 
canals.  Their  cut  ends  may  be  seen  at  the  tip  of  the  cut-off 
rays.  The  tube  feet  are  connected  to  the  radial  canals  by 
short  tubes  running  to  the  right  and  left.  This  whole  sys- 
tem of  tubes  is  called  the  water-vascular  system.  (See  text 
for  manner  of  locomotion  by  means  of  this  system.) 

Make  a  diagram  of  the  water-  vascular  system. 

C.  TOPICS  FOR  FURTHER  STUDY.  Compare  several 
starfish,  noting  the  differences  in  size  and  shape  of  the  arms 
and  central  disk.  Compare  with  the  brittle  stars  and  sea 


30  STUDIES   OF   ANIMAL  TYPES 

urchins.  Note  the  spines  on  the  body  of  the  sea  urchin. 
Remove  the  spines  and  note  the  globular  shell.  Note  the 
five  areas  of  the  sea-urchin's  shell. 

To  what  branch  does  the  starfish  belong?  What  other 
animals  belong  to  this  branch?  What  is  characteristic 
of  the  skin  of  the  starfish  ?  What  kind  of  symmetry  has 
its  body?  All  the  members  of  this  branch  possess  the 
same  body  symmetry.  Compare  with  the  symmetry  of  the 
body  of  the  locust.  Note  that  the  starfish  has  a  set  of 
tubes  for  the  circulation  of  water.  What  is  the  nature  of 
the  organs  of  locomotion?  Most  of  the  other  members 
of  this  branch  possess  the  same  kind  of  organs.  Make  a 
summary  of  the  digestive  organs  of  this  echinoderm. 

X.  —  THE  EARTHWORM 

Materials.  —  Living  and  preserved  earthworms,  piece  of  glass, 
tooth  picks,  dissecting  instruments,  wax-lined  dissecting  pan,  pins, 
magnifier. 

Directions.  —  (Earthworms  may  be  obtained  after  a  warm  rain 
in  spring  by  simply  picking  them  from  the  ground.  Failing  in  this, 
they  may  be  procured  by  digging  in  the  soil.  They  will  be  found 
more  abundant  in  rich  soils.  Large  specimens  for  dissection  may  be 
had  of  dealers  in  such  supplies.) 

A.  STUDY  OF  A  LIVING  EARTHWORM.  Place  a  live  worm 
on  a  rough  surface,  for  instance,  the  top  of  a  table  or  sheet 
of  paper.  Watch  its  movements.  Does  it  move  with  the 
same  end  always  foremost?  Can  it  move  backward? 
Does  it  hold  the  same  side  of  the  body  uppermost  ?  Turn 
it  over  and  note  the  results.  Note  the  lengthening  and 
shortening  of  the  body  when  it  moves.  Has  the  earth- 
worm any  visible  locomotor  appendages  ? 


THE    EARTHWORM  31 

Draw  one  backward  across  the  hand.  What  is  the  sen- 
sation? What  is  this  due  to?  How  many  rows  of  the 
bristles  are  there?  (Use  the  magnifier  to  determine  this.) 

Place  the  worm  on  a  piece  of  glass.  Can  it  progress? 
Why  this  difference  in  the  progression  of  the  earthworm 
on  a  smooth  and  on  a  rough  surface  ?  What  are  the  bristles, 
or  setce,  for?  Determine  which  way  the  setae  point. 

Determine  the  sensitiveness  of  different  parts  of  the  body 
by  touching  it  in  different  places  with  the  tooth  pick. 

Note  the  blood  tube  along  the  middle  of  the  back  just 
under  the  thin,  transparent  skin.  Can  pulsations  in  this 
tube  be  seen  ?  If  so,  they  would  indicate  a  circulation  of 
the  blood.  Determine,  if  possible,  which  way  the  blood  is 
flowing  in  this  tube. 

B.  EXTERNAL  FEATURES.  Note  the  long,  tapering, 
cylindrical  body.  Is  it  one  unbroken  cylinder  like  a  pencil  ? 
The  rings  are  called  segments.  How  many  segments  are 
there  in  the  body  ?  The  end  of  the  body  that  was  usually 
carried  foremost  while  the  worm  was  moving  is  the  anterior 
end,  and  the  opposite  end  is  the  posterior  end.  The  side  of 
the  body  held  uppermost  away  from  the  ground  is  the 
dorsal  side,  and  the  opposite  side  is  the  ventral  side.  Is 
there  any  difference  between  the  dorsal  and  ventral  sides 
in  color  and  shape?  If  a  cross  section  of  the  body  were 
made,  would  it  be  a  perfect  circle  ?  Which  side  would  be 
flat  and  which  would  be  round  ? 

Note  that  if  the  worm  were  cut  in  half  lengthwise  the 
right  half  would  be  similar  to  the  left  half.  This  two- 
sided  likeness  is  known  as  bilateral  symmetry,  and  the  earth- 
worm is  a  bilaterally  symmetrical  animal. 

Note  the  thickened,  or  swollen  ring,  the  clitellum,  near 
the  anterior  end.  Does  it  embrace  more  than  one  segment  ? 


32  STUDIES  OF  ANIMAL  TYPES 

Find  the  mouth  at  the  anterior  end  of  the  body.  Note 
that  it  is  overhung  by  a  projection,  the  lip,  or  prostomium. 

Find  the  anal  aperture,  or  vent,  at  the  posterior  end  of 
the  body. 

Make  a  drawing  of  the  body  from  a  dorsal  view. 

C.  INTERNAL  FEATURES.  With  sharp  scissors,  make  a 
shallow  incision  through  the  skin,  along  the  median  line  of 
the  back,  the  whole  length  of  the  body,  being  very  careful 
not  to  injure  any  of  the  organs  beneath.  Draw  the  edges 
of  the  cut  skin  apart  and  pin  down  with  ribbon  pins, 
beneath  water  in  the  dissecting  pan. 

Note  the  delicate  partitions,  or  septa,  across  the  body 
cavity,  dividing  it  into  chambers  corresponding  to  the  ring- 
like  divisions  of  the  walls.  Note  the  alimentary  canal 
extending  as  a  straight  tube  the  whole  length  of  the  body. 
It  consists  of  a  pharynx,  gullet,  crop  in  segments  15  and  16, 
and  a  gizzard  in  segments  17  to  19.  The  remaining  part 
is  the  intestine. 

Note  three  pairs  of  large  white  bodies  surrounding  the 
gullet.  These  are  the  seminal  vesicles.  Posterior  to  these 
are  two  smaller  sacs,  the  seminal  receptacles. 

Note  the  large  blood  vessel  on  the  dorsal  side  of  the  ali- 
mentary canal.  In  segments  7  to  11  will  be  seen  several 
branches  from  this  blood  vessel  going  around  the  alimentary 
canal  and  meeting  a  ventral  blood  vessel  below. 

Make  a  drawing  showing  these  organs. 

Cut  the  alimentary  canal  in  two  at  the  pharynx  and 
remove  the  posterior  portion.  Note  the  ventral  blood 
vessel  beneath.  Beneath  this  note  the  large  white  double 
cord  running  the  whole  length  of  the  body.  This  is  the 
nerve  cord.  Note  in  each  segment  a  white  knot,  or  swell- 
ing, a  double  ganglion.  Trace  the  nerve  cord  forward  and 


THE    EARTHWORM  33 

find  where  it  divides  near  the  anterior  end.  One  branch 
goes  up  one  side  of  the  gullet  and  the  other  up  the  opposite 
side,  after  which  they  meet  on  top  of  the  alimentary  canal 
to  form  the  brain. 

In  most  of  the  segments  will  be  seen  a  small,  much  con- 
voluted tube,  the  nephridium.  The  nephridia  are  the  or- 
gans of  secretion.  Each  one  opens  outward  on  the  ventral 
side  of  the  body  through  a  pore.  They  carry  off  the  waste 
products  of  the  body. 

The  earthworm  is  hermaphroditic  and  has  both  the  male 
and  female  reproductive  organs.  Beneath  the  seminal 
vesicles  already  noted  will  be  found  the  testes.  These  open 
outward  through  a  pair  of  ducts  that  extend  backward  to 
the  fifteenth  segment. 

The  ovaries  may  be  found,  with  difficulty,  in  segment  18. 
They  are  a  pair  of  small  white  bodies.  The  ova  pass  from 
the  ovaries  into  funnel-shaped  oviducts  that  open  on  the 
ventral  side  of  the  body  through  segment  14. 

Make  a  drawing  showing  these  points. 

D.  FIELD    STUDY    OF    THE    EARTHWORM.    Study    the 
earthworm  in  the  field.     When  is  it  found  on  top  of  the 
ground,  during  the  night  or  day,  when  the  air  is  dry  or 
moist?    What  is  the  shape  of  its  burrow?    How  deep  is 
the  burrow  ?    What  is  often  found  piled  around  the  mouth 
of  the  burrow  ?    These  are  pellets  of  earth  and  refuse  food 
that  have  passed  through  the  alimentary  canal  and  are 
termed  castings.    Note  the  ease  and  quickness  with  which 
an  earthworm  can   retreat  into  its  burrow.     Note  how 
difficult  it  is  to  pull  one  out  of  its  burrow.     Why  is  this  ? 

E.  TOPICS  FOR  FURTHER  STUDY.     Write  out  the  chief 
characteristics  of  the  earthworm,  remembering  the  division 
of  the  body  into  definite  segments.     Make  a  diagrammatic 

HERRICK  LAB.  EX. 3 


34  STUDIES  OF  ANIMAL  TYPES 

cross  section  of  the  body  showing  the  organs.  Summarize 
the  processes  of  digestion,  circulation,  excretion,  and  res- 
piration as  carried  on  in  the  earthworm. 

XI.  —  THE  RIVER  MUSSEL 

Materials.  —  Living  mussels,  carmine  or  India  ink,  dissecting  in- 
struments, dissecting  pan,  magnifier,  hydrochloric  acid,  balances, 
bristles. 

Directions.  —  (The  following  outline  applies  especially  to  the 
river  mussel  (Unio)  that  is  common  in  the  ponds  and  streams  of  the 
United  States.  The  marine  clams  (Venus  and  Mya)  will  serve  quite 
as  well.  These  may  be  obtained  of  dealers  in  zoological  specimens. 
The  river  mussel  may  be  carried  home  in  water,  and  kept  in  an  aqua- 
rium containing  several  inches  of  sand  in  the  bottom.) 

A.  STUDY  OF  A  LIVING  MUSSEL.  Carefully  watch  a  liv- 
ing specimen  in  the  aquarium.  In  what  position  is  the 
shell  held  when  the  animal  is  moving?  Is  the  movement 
slow  or  rapid  ?  Does  the  mussel  leave  a  track,  or  furrow,  in 
the  mud?  Is  the  shell  open  or  closed  when  the  mussel 
is  moving?  Note  a  white  fleshy  projection  between  the 
anterior  edges  of  the  shell.  This  is  the  foot.  Note  that  the 
mussel  moves  in  one  direction  with  the  anterior  end  fore- 
most. Is  the  broad  or  sharp  edge  of  the  shell  held  upper- 
most ?  From  the  posterior  edges  of  the  shell  may  be  seen 
projecting  two  rounded,  fringed  openings,  the  siphons. 
By  placing  some  carmine  or  India  ink  in  the  water  near 
them,  the  direction  of  the  currents  of  water  may  be  deter- 
mined. Through  which  siphon  does  the  water  enter? 
Through  which  does  it  emerge?  In  moving,  the  valves 
are  held  partly  open  and  the  edge  of  the  delicate  mantle 
may  be  seen  all  around  the  edges  of  the  shell. 


THE    KIVER    MUSSEL  35 

B.  EXTERNAL  FEATURES  OF  THE  SHELL.    Of  how  many 
pieces  is  the  shell  composed  ?    Are  they  of  the  same  shape 
and  size?    These  pieces  are  called  the  valves.    Note  that 
they  are  joined  or  hinged  together  along  the  broad  edges. 
These  edges  are  held  uppermost  by  a  living  mussel  when  it 
is  moving,  and  this  side  of  the  shell  is  therefore  known  as 
the  dorsal  margin.      The  thin  edge  of  the  shell  is  called 
the  ventral  side  or  margin.    Note  the  concentric  lines  run- 
ning parallel  with  the  ventral  edges  of  the  shell.     These  are 
the  lines  of  growth.    They  all  begin  and  end  around  a  raised 
point  near  the  anterior  end  of  each  valve.    This  point  is 
called  the  umbo,  or  beak. 

Knowing  the  dorsal  side  of  the  shell  a"nd  its  anterior 
end  determine  which  is  the  right  valve  and  which  the  left. 

Draw  a  side  view  of  the  left  valve  showing  all  the  fore- 
going points  possible. 

C.  THE  MUSSEL  IN  THE  SHELL. 

(For  dissection,  the  valves  must  be  opened.  To  do  this,  place  the 
animal  in  warm  water,  about  as  hot  as  the  hand  can  bear.  The 
valves  will  gape,  and  a  block  may  be  slipped  between  them  to  hold 
them  dpen.) 

Note  the  mantle  lining  the  inside  of  the  valves.  With 
the  handle  of  a  scalpel,  separate  the  edge  of  the  mantle 
from  the  upper  valve.  Observe  that  it  is  loose  to  a  line 
some  little  distance  from  the  edge  of  the  valve.  Beyond 
this  line  the  mantle  is  grown  tight  to  the  valve.  This  line 
is  known  as  the  pallial  line.  With  the  scalpel,  carefully 
tear  the  mantle  loose  from  the  valve  that  is  uppermost, 
and  then  cut  away  the  strong  muscles  that  hold  the  valves 
together.  Note  that  the  valves  spring  apart  as  this  is 
done.  Find  the  strong  ligament,  near  the  umbo,  that  acts 
as  a  hinge.  Note  the  hinge  teeth  on  the  dorsal  edges  of 


36  STUDIES    OF   ANIMAL   TYPES 

the  valves.    Observe  how  closely  they  fit  together.     Re- 
move the  uppermost  valve. 

(Further  dissection  is  best  done  under  water.  The  water  will 
cause  the  different  parts  to  float  separate  from  each  other  so  that 
they  may  be  easily  distinguished.) 

Note  that  the  mantle  lines  the  inside  of  both  valves  and 
completely  surrounds  the  body.  Observe  the  two  siphons 
at  the  posterior  end  of  the  shell.  Note  that  they  are  formed 
by  the  mantle.  The  lower  one  is  the  inhalent  and  the  upper 
one  the  exhalent  siphon.  Note  at  each  end  of  the  shell  a 
very  large  thick  muscle  that  was  cut  by  the  scalpel.  The 
muscle  at  the  posterior  end  is  the  posterior  adductor  muscle. 
The  one  at  the  anterior  end  is  the  anterior  adductor  muscle. 
They  hold  the  valves  tightly  shut.  Observe  beside  each 
one  smaller  oblique  muscles,  the  anterior  and  posterior 
retractor  muscles,  respectively. 

Turn  back  the  half  of  the  mantle  torn  from  the  valve.  The 
space  inclosed  by  the  two  lobes  of  the  mantle  is  called  the 
mantle  cavity.  In  this  mantle  cavity,  as  the  lobe  is  turned 
back,  note  the  two  pairs  of  thin,  ribbed  gills,  a  pair  on  each 
side  of  the  body.  Note  the  soft  white  abdomen  between 
them.  The  water,  laden  with  food,  is  taken  through  the 
inhalent  siphon  into  the  mantle  cavity.  The  food  is  passed 
into  the  mouth,  but  the  water  passes  through  the  gills, 
aerating  the  blood,  and  finally  goes  out  through  the  exhalent 
siphon. 

Loosen  the  mantle  and  body  on  the  dorsal  side  very 
carefully  and  pull  them  a  little  from  the  remaining  valve. 
This  will  bring  the  dorsal  side  of  the  body  into  view.  On 
the  middle  line  of  the  dorsal  side  cut  carefully  through  the 
mantle  and  the  other  delicate  tissue  until  a  cavity  is  laid 


THE   RIVER   MUSSEL  37 

t 

open.  This  is  the  pericardial  cavity.  Within  it,  is  a  dark 
tube,  the  intestine,  which  runs  straight  through  the  cavity. 
The  ventricle  of  the  heart  surrounds  the  intestine  about 
midway  of  its  length.  The  auricles,  right  and  left,  are  at- 
tached to  the  right  and  left  sides  of  the  ventricle,  respec- 
tively. The  blood  is  brought  to  the  auricles  from  the  gills 
by  the  two  branchial  veins,  one  to  each  auricle.  It  is  then 
emptied  by  the  auricles  into  the  ventricle.  From  here  it  is 
forced  through  the  anterior  and  posterior  aortas  to  the  differ- 
ent parts  of  the  body. 

On  either  side  of  the  front  part  of  the  abdomen  are  two 
soft,  triangular  flaps,  the  labial  palpi.  Between  these  and 
directly  in  front  is  the  mouth.  It  leads  by  a  short  gullet 
to  the  stomach,  which  is  surrounded  by  a  dark  mass,  the 
liver.  The  liver  is  plainly  discernible.  The  intestine  may 
be  traced  from  the  stomach  by  using  a  bristle.  It  makes 
several  turns  before  it  runs  through  the  pericardial  cavity. 
Remove  the  heart  and  note  beneath  it  the  kidneys,  or  renal 
organs. 

Beneath  the  posterior  adductor  muscle  is  a  pair  of  yellow- 
ish white  ganglia.  These  are  the  visceral  ganglia.  They 
give  off  several  nerves  that  run  to  the  mantle  and  gills. 
Two  nerves  also  run  from  the  visceral  ganglia  to  join  a  pair 
of  ganglia  near  the  mouth.  From  the  latter,  a  pair  of  nerves 
run  to  the  pedal  ganglia,  which  lie  deeply  imbedded  where 
the  foot  and  the  abdomen  meet. 

Make  a  drawing  showing  as  many  of  these  points  as 
possible. 

D.  INTERNAL  FEATURES  OF  THE  SHELL.  Remove  the 
body  of  the  mussel  from  the  shell. 

Note  the  color  of  the  shell  lining  and  its  smooth,  pearly 
finish. 


38  STUDIES   OF  ANIMAL  TYPES 

Note  the  hinge  teeth  along  the  dorsal  edges.  How  many 
are  there  on  each  valve  ?  Note  how  they  fit  together  and 
interlock  with  one  another.  Of  what  use  are  they  ? 

Note  and  number  the  muscle  scars,  two  at  the  anterior 
end  of  the  valve  and  two  at  the  posterior  end.  At  the 
anterior  end  near  the  dorsal  margin  is  the  large  anterior 
adductor  muscle  scar  and  above  and  just  posterior  to  this 
is  the  small,  obscure  anterior  retractor  muscle  scar.  At  the 
posterior  end  of  the  valve  and  near  the  dorsal  margin  is 
the  large  posterior  adductor  muscle  scar.  Above  and  just  in 
front  of  this  is  the  small  posterior  retractor  muscle  scar. 

Also  note  the  pallial  line  parallel  with  the  ventral  edge 
of  the  valve. 

Make  a  drawing  to  show  these  points. 

E.  STRUCTURE  OF  THE  SHELL.    Break  the  shell  and  ex- 
amine the  broken  edge  with  a  hand  lens.     Note  that  it 
consists  of  three  layers.     The  inner  layer  is  composed  of 
mother-of-pearl  and  is  secreted  by  the  mantle.     The  middle 
layer,  which  is  dark  in  color,  consists  of  many-sided  prisms 
placed  at  right  angles  to  the  surface  of  the  shell.    The 
outer  layer  forms  the  greenish  or  brownish  epidermis. 

Place  a  shell  in  dilute  hydrochloric  acid  until  the  mineral 
matter  is  all  dissolved  out.  What  is  the  characteristic  of 
the  remaining  portion?  This  portion  is  composed  of  the 
animal  matter  and  is  called  conchiolin. 

Weigh  a  shell  and  then  burn  out  the  animal  matter  in  the 
fire.  Weigh  again  and  determine  the  loss  if  any. 

F.  TOPICS  FOR  FURTHER  STUDY.   Outline  the  processes  of 
digestion,  circulation,  and  respiration  in  this  animal.  Write 
out  the  chief  characteristics  of  the  mussel.     Fix  firmly  in 
mind  its  position  in  the  animal  kingdom.     Make  a  study 
of  its  near  relatives,  the  marine  clams,  oysters,  etc. 


THE    SQUID  39 

XII.  — THE  SQUID 
Materials.  —  Specimens  of  squid. 

Directions.  —  (The  squid  is  a  marine  mollusk.  It  is  common 
along  the  shores  of  the  United  States,  and  may  be  obtained  from 
any  of  the  dealers  in  zoological  supplies.  A  half  dozen  or  so  should 
be  in  the  collection  for  comparison  with  the  clam  and  other  mol- 
lusks.) 

Note  the  long,  cylindrical  body,  with  a  distinct  head. 
Does  it  possess  a  shell  like  the  clam  or  oyster  ?  Imbedded 
in  the  thick  mantle  straight  down  the  back  is  a  rudimentary 
shell  known  as  the  pen.  Did  the  clam  possess  a  distinct 
head?  Note  on  the  head  of  the  squid  the  long  arms,  or 
tentacles.  How  many  pairs  are  there?  Note  that  one 
pair  is  longer  than  the  other  pairs.  Note  the  sucker  disks 
on  the  inside  of  the  short  arms.  Note  that  the  long  arms 
do  not  bear  the  suckers  the  whole  length,  but  only  on  an 
expanded  portion  near  the  end.  How  many  rows  of  the 
cuplike  suckers  on  this  expanded  portion?  Are  they  all 
of  the  same  size  ?  Note  in  the  middle  of  the  cluster  of  arms, 
at  their  bases,  the  mouth.  Note  the  black,  horny  beak, 
something  like  the  beak  of  a  parrot. 

How  many  eyes  has  the  squid  ?  Where  are  they  ?  Did 
the  clam  have  eyes?  At  the  posterior  part  of  the  body, 
note  the  triangular  flaps  of  skin.  These  are  the  so-called 
fins.  They  are  used  to  guide  the  animal  in  swimming. 

Make  a  drawing  of  the  dorsal  side  of  the  animal. 

Beneath  the  skin  of  the  body  are  numerous  pigment 
cells.  They  appear  like  freckles  all  over  the  dorsal  side 
and  are  usually  purplish  in  color.  These  cells  can  be  ex- 
panded until  they  touch  one  another  or  suddenly  contracted 


40  STUDIES    OF   ANIMAL   TYPES 

until  each  one  stands  by  itself  as  a  minute  dot.  At  every 
successive  contraction  and  expansion  of  the  pigment  cells, 
in  a  living  specimen,  blushes  of  different  hues  may  be 
observed  passing  over  the  body. 

Note  that  the  head  seems  to  sit  down  in  a  collar  of  thick 
skin,  or  flesh.  This  is  the  anterior  end  of  the  thick,  fleshy 
mantle  that  covers  all  of  the  body  except  the  head.  Is  the 
head  grown  to  the  mantle?  How  does  the  mantle  com- 
pare with  the  mantle  of  the  clam  ?  Beneath  the  head,  note 
the  siphon.  Under  ordinary  conditions,  the  water,  for  re- 
spiratory purposes,  passes  in  and  out  through  the  aperture 
between  the  mantle  and  the  neck.  But  when  the  animal 
desires  to  swim  the  mantle  contracts  and  closes  up  the 
opening  about  the  neck,  and  the  water  is  forced  out  through 
the  siphon. 

Make  a  written  comparison  of  the  clam  and  squid. 

XIII. — THE  HABITS  AND  LIFE  HISTORY  OF  A  POND 

SNAIL 

Materials.  —  Specimens  of  Physa  (alive) . 

Directions.  —  (The  two  common  pond  snails,  Limnea  and  Physa, 
are  abundant  in  many  ponds.  They  may  be  dipped  up  and  kept  in 
jars  of  water  almost  any  length  of  time,  if  some  pond  scum  and 
lettuce  leaves  are  added  for  them  to  eat.  The  following  outline 
applies  especially  to  the  smaller  one,  Physa.) 

A.  STUDY  OF  A  LIVING  SNAIL.  Note  the  color  of  the 
shell.  What  is  its  shape?  Is  it  a  flat  or  an  ascending 
spiral?  Does  it  coil  to  the  right  or  left?  Note  that  it 
consists  of  one  piece  or  valve.  Compare  it  with  the  clam. 
Watch  some  of  the  individuals  climb  up  the  sides  of  the 
jar.  They  progress  swiftly,  with  a  smooth,  gliding  move- 


THE    HABITS   AND    LIFE    HISTORY    OF   A    POND    SNAIL      41 

ment.  Some  will  be  seen  swimming  along  the  surface  of 
the  water.  In  what  position  are  they?  Note  the  move- 
ments of  swimming.  Note  that  the  portion  of  the  body 
outside  of  the  shell  is  triangular  in  shape.  The  greater  part 
of  this  is  the  foot.  Note  in  a  swimming  specimen  the 
mouth,  which  is  a  small  aperture  that  opens  and  shuts 
rythmically.  It  is  on  the  under  side  of  the  head.  Note 
that  the  triangular  foot  ends  squarely  just  behind  the  head. 
Watch  one  come  to  the  top  and  turn  on  its  back.  As  it  does 
so,  note  the  round  opening  just  inside  of  the  shell.  This 
is  the  respiratory  opening  and  it  leads  to  the  lung.  The 
snails  come  to  the  surface  at  intervals  to  take  in  air  through 
this  opening.  Touch  an  individual  with  a  pencil.  Does  it 
drop  to  the  bottom  ?  As  it  does  so  what  does  it  give  off  ? 
The  lung  is  used  as  a  hydrostatic  apparatus  as  well  as  for 
breathing.  When  the  snail  wishes  to  descend  for  safety,  it 
gives  out  from  the  lung  one  or  more  bubbles  of  air;  this 
causes  the  body  to  become  heavier. 

Make  a  drawing  of  the  snail,  as  it  is  swimming  on  the  sur- 
face of  the  water,  to  show  its  foot  and  head  with  the  mouth. 

How  many  tentacles  has  this  snail  ?  Where  are  the  eyes  ? 
How  many  are  there  ? 

Make  a  drawing  of  the  shell  from  above. 

B.  LIFE  HISTORY  OF  THE  SNAIL.  If  these  snails  were 
brought  into  the  house  in  February  or  March,  the  eggs 
may  soon  be  found  on  the  sides  of  the  jar,  or  on  leaves, 
sticks,  etc.  They  will  appear  as  transparent,  gelatinous 
masses,  about  the  shape  and  size  of  half  of  a  pea  or 
bean.  Note  the  number  of  eggs  in  each  mass.  Mount  a 
few  of  them  on  a  slide,  and  examine  with  a  J  objective. 
What  is  the  shape  of  a  single  egg  ?  Note  the  transparent 
capsule;  like  a  shell,  about  each  one.  If  they  are  nearly 


42  STUDIES    OF   ANIMAL   TYPES 

fresh  eggs  the  embryo  may  be  seen,  occupying  only  a  very 
small  portion  of  the  egg.  As  they  grow  older  the  embryo 
enlarges,  the  shell  begins  to  form,  and  the  young  snail  keeps 
constantly  turning  round  and  round  in  the  egg.  At  this 
stage,  note  the  two  dark  spots  —  the  eyes  —  on  the  head. 

Make  a  drawing  showing  a  young  egg  with  its  nearly 
spherical  embryo,  and  then  an  older  stage,  with  the  more 
advanced  embryo. 

If  possible,  keep  the  eggs  until  the  young  snails  come  out. 
Note  the  time  it  took  the  eggs  to  hatch. 

These  snails  have  the  power  of  spinning  a  thread,  which 
they  may  use  to  ascend  or  descend  in  the  water. 

Limnsea  lays  its  eggs  later  in  the  season  in  much  the 
same  situations.  Limna3a  should  be  fed  daily  on  cabbage 
or  lettuce  leaves.  On  these  leaves,  areas  that  have  been 
scraped  by  the  lingual  ribbon  of  the  snail  may  be  seen. 

XIV.  —  THE  CRAYFISH 

Materials.  —  Specimens  of  crayfish  (alive  and  preserved  in  for- 
malin), dissecting  instruments,  dissecting  pan. 

Directions.  —  (The  crayfish  is  common  everywhere  in  brooks, 
ponds,  and  pools.  In  many  localities,  especially  in  the  southern 
states,  some  species  dig  holes  in  the  ground  and  build  clay  chimneys 
about  the  mouths  of  the  tubes.  Crayfish  may  be  caught  by  hook 
and  line  or  scooped  up  with  a  net.) 

A.  STUDY  OF  A  LIVING  CRAYFISH.  It  will  be  of  great 
interest  to  observe  them  in  their  natural  homes.  Note  the 
manner  of  movement  in  the  water.  In  how  deep  water  do 
they  live?  In  what  character  of  soil  do  those  live  that 
build  chimneys  ?  How  deep  are  the  holes  ?  Determine,  if 
possible,  what  is  at  the  bottoms  of  the  holes.  Do  the  cray- 


THE    CRAYFISH  43 

fish  ever  come  out  of  their  burrows  ?  Is  the  inside  of  the 
burrow  smooth  or  rough?  How  high  is  the  chimney  and 
how  is  it  constructed?  Does  this  crayfish  ever  do  any 
harm  ?  On  what  does  it  live  ? 

Catch  a  live  specimen  and  put  it  in  an  aquarium.  Note 
its  manner  of  movement.  How  many  legs  does  it  use  in 
locomotion?  Poke  a  stick  or  straw  at  its  head.  Which 
way  and  how  does  it  move?  How  is  the  abdomen  held? 
Note  the  eyes  of  the  animal.  Note  its  feeding  habits.  What 
does  it  eat  ?  How  does  it  catch  its  prey  ? 

B.  EXTERNAL  FEATURES.  Note  that  the  body  of  the 
crayfish  is  divided  into  two  principal  regions.  The  anterior 
region  consists  of  the  head  and  thorax  joined  together  and 
appears  as  one  piece.  This  is  called  the  cephalothorax.  The 
posterior  division  is  the  abdomen.  Note  that  the  abdomen 
is  plainly  segmented.  Does  this  aid  in  the  movements  of 
the  animal?  Note  that  the  whole  body  is  encased  in  a 
hard  covering,  or  crust.  This  crust  is  hardened  by  a  de- 
position of  lime  carbonate.  As  the  crayfish  grows,  this  crust, 
or  hardened  skin,  is  shed  from  time  to  time. 

Make  a  drawing  of  the  crayfish  from  above. 

Note  that  the  cephalothorax,  when  viewed  from  above, 
shows  no  signs  of  being  segmented.  Look  on  the  ventral 
surface,  however,  and  the  division  into  segments  may  be 
seen.  Note  that  the  top  of  the  cephalothorax  is  covered 
with  a  single  large  piece  called  the  carapace.  The  division 
between  the  head  and  thorax  is  marked  by  a  shallow 
groove  that  runs  transversely  across  the  carapace,  and 
then  continues  forward  in  an  oblique  direction  on  each 
side.  Note  that  the  carapace  in  front  extends  forward  be- 
tween the  eyes,  forming  a  concave  pointed  beak.  This  is 
known  as  the  rostrum. 


44  STUDIES   OF   ANIMAL   TYPES 

Note  the  number  of  segments  in  the  abdomen.  How 
many  appendages  does  the  fourth  segment,  for  instance, 
bear  ?  What  is  the  general  shape  of  this  segment,  and  on 
what  part  of  it  are  the  appendages  borne?  The  convex 
piece  on  the  dorsal  side  is  called  the  tergum.  The  piece  on 
each  side  that  slopes  like  the  side  of  a  roof  is  called  the 
pleurum.  The  transverse  piece  on  the  ventral  side  be- 
tween the  two  appendages  is  called  the  sternum.  How  are 
the  segments  of  the  abdomen  connected  with  each  other? 
Why? 

The  appendages  of  the  crayfish.  —  Now  look  at  the  end  of 
the  abdomen  and  note  that  it  ends  in  five  flaplike  bodies, 
each  fringed  around  the  end.  The  broad  middle  flap  is  the 
last  segment  of  the  abdomen,  and  is  known  as  the  telson. 
The  two  flaps  on  each  side  of  the  telson  are  the  greatly 
modified  appendages  of  the  next  abdominal  segment  an- 
terior to  the  telson.  These  flaps  are  in  pairs,  and,  together 
with  the  telson,  form  the  tail  fin  of  the  crayfish. 

The  crayfish  has  nineteen  pairs  of  appendages.  Note  that 
the  last  segment,  the  telson,  bears  no  appendages.  The  next 
segment,  the  sixth,  bears  the  two  pairs  of  fringed  flaps  that 
have  already  been  spoken  of  as  forming  a  part  of  the  tail 
fin.  The  next  five  abdominal  segments  bear  each,  one  pair 
of  appendages,  which  are  called  the  swimmerets.  These 
appendages  are  all  alike  except  those  on  the  first  and  second 
segments,  which  are  reduced  and  smaller,  or  perhaps  lack- 
ing entirely  in  the  female. 

Note  that  each  appendage  consists  of  a  short,  twice- 
segmented  stalk,  bearing  two  narrow,  flat,  fringed  filaments, 
like  a  two-tined  fork. 

The  next  five  pairs  of  appendages  are  the  legs  attached 
to  the  thorax.  Note  that  the  fourth  and  fifth  pairs  end 


THE    CRAYFISH  45 

with  one  short  claw,  while  the  other  three  pairs  end  in 
double  claws,  which  are  very  large  on  the  first  pair.  How 
many  segments  in  each  leg  ? 

After  having  examined  the  appendages  as  directed,  begin 
at  the  most  posterior  one,  and  remove  those  of  the  abdomen 
from  the  right  side,  being  careful  to  keep  them  in  their 
proper  order.  When  the  legs  are  reached,  before  removing 
them,  expose  the  gills.  To  do  this  begin  at  the  posterior 
end  of  the  carapace,  and  cut  through  it  with  a  pair  of 
scissors,  along  the  middle,  until  the  line  separating  the 
head  and  thorax  is  reached.  Then  follow  this  line  to  its 
anterior  end.  Break  off  the  piece  of  the  carapace  so  cut, 
and  the  gills  will  be  exposed.  Note  their  feathery  ap- 
pearance. Note  that  they  lie  in  a  chamber  completely 
hidden  from  above  by  the  carapace.  Do  they  fill  this 
chamber?  Where  does  the  water  get  into  the  chamber? 
Note  that  the  gills  are  arranged  in  layers,  or  series.  One 
layer,  or  series,  is  attached  to  the  bases  of  the  legs  while 
the  other  series  is  attached  to  a  thin,  transparent  mem- 
brane. Now  remove  each  leg  with  its  gill  and  lay  them  in 
order  after  the  other  detached  appendages.  The  thorax 
has  three  more  pairs  of  appendages  immediately  in  front 
of  the  large  pair  of  legs.  These  three  pairs  entirely  cover 
the  mouth.  Push  them  to  one  side  and  note  the  mouth 
hidden  by  them.  These  appendages  are  called  the  foot- 
jaws,  or  maxillipeds.  They  are  used  to  aid  in  grinding  the 
food. 

Remove  the  posterior  maxilliped.  Note  that  it,  like  a 
swimmeret,  has  a  twice  segmented  stalk  with  two  branches, 
but,  unlike  the  swimmeret,  it  bears  a  gill.  Remove  the 
next  maxilliped.  Has  it  all  of  the  parts  of  the  first  one? 
What  is  the  difference  in  the  size  of  the  two  detached  maxil- 


46  STUDIES   OF  ANIMAL  TYPES 

lipeds?  Remove  the  next,  or  first,  maxilliped.  Has  it  a 
gill?  How  does  it  compare  in  size  with  the  other  two? 
This  completes  the  appendages  of  the  thorax,  for  the  re- 
maining ones  belong  to  the  head. 

The  next  two  pairs  of  appendages  are  thin  and  delicate, 
and  one  must  hunt  for  them  carefully.  They  correspond 
to  the  lower  jaws  of  the  locust,  and  are  given  the  same 
name,  maxillce.  After  they  have  been  located  and  sepa- 
rated from  each  other  (they  lie  directly  in  front  of  the  first 
pair  of  maxillipeds),  note  a  sort  of  curved,  spoon-shaped 
plate  on  the  second  maxilla.  It  moves  back  and  forth  in 
the  anterior  opening  of  the  gill  chamber,  and  scoops  the 
water  out  of  the  chambers,  as  it  were,  thus  giving  oppor- 
tunity for  fresh  water  to  enter  from  behind.  The  next  pair 
of  appendages  is  the  mandibles.  Each  is  hard,  with  toothed 
edges,  and 'each  has  attached  to  its  anterior  edge  a  short, 
curved  appendage,  known  as  the  palpus.  These  should  be 
compared  with  the  mandibles  of  a  locust. 

Now  note  the  next  pair  of  appendages,  the  two  long 
antenncB.  Above  each  antenna,  but  beneath  the  eye,  is  a 
flat,  bladelike  branch  of  the  antenna.  It  probably  pro- 
tects the  eye.  Note  that  the  eyes  are  stalked.  Pull  out 
the  eye  and  note  the  length  of  the  stalk.  The  stalk  can 
turn  the  eye  so  that  it  can  look  in  any  direction. 

Lastly  note  the  pair  of  small,  branched  antennae  known 
as  the  antennules. 

Make  a  drawing  of  all  the  appendages  of  the  right  side 
after  having  placed  them  in  order. 

Note  the  great  similarity  in  structure  of  these  organs  not- 
withstanding their  diversity  of  function. 

C.  TOPICS  FOR  FURTHER  STUDY.  To  what  branch 
does  the  crayfish  belong?  What  other  animals  belong  to 


OTHER    CRUSTACEANS  47 

this  same  branch  ?  To  what  class  does  it  belong  ?  Name 
the  other  animals  belonging  to  the  same  class.  Compare  the 
crayfish  with  a  lobster. 

Sum  up  the  chief  characteristics  of  the  crayfish.  Fix 
firmly  in  mind  its  position  in  the  animal  kingdom.  Give 
a  summary  of  its  habits,  food,  habitats,  and  economic  im- 
portance. Write  out  a  comparison  between  it  and  the 
locust. 

XV.  —  OTHER  CRUSTACEANS 

Materials.  —  Specimens  of  cyclops,  cypris,  daphnia,  crabs  (Rock 
and  Hermit) ;  watch  glass. 

Directions.  —  (Cyclops,  cypris,  and  daphnia  are  small  crus- 
taceans that  live  in  fresh-water  ponds.  They  may  be  obtained  in 
abundance  in  jars  of  pond  water  containing  Algae  that  have  been 
brought  into  the  laboratory.  Though  small,  they  are  visible  to  the 
unaided  eye.) 

A.  CYCLOPS.  Take  some  of  these  out  in  a  watch  crystal, 
and  observe,  carefully,  their  movements.  Is  the  progres- 
sion a  smooth,  gradual  one  or  a  jerky  one?  Their  mode 
of  motion  has  given  them  the  name  of  "  water  fleas." 

Note  the  shape  of  the  body,  large  at  the  anterior  end  and 
tapering  to  the  posterior  end,  convex  above  and  flat  below. 

Note  the  one  dark  eye  at  the  anterior  end  of  the  body 
on  the  dorsal  side.  Note  the  two  long  appendages  at  the 
anterior  end  of  the  body,  called  the  antennules.  There  is 
also  a  pair  of  short  antennae  that  are  often  hidden  beneath 
the  head.  Observe  that  there  are  five  pairs  of  appendages 
on  the  ventral  side  of  the  body.  The  body  is  segmented, 
but  note  the  large  piece  covering  the  anterior  end  of  the 
body.  This  is  the  carapace.  The  tip  of  the  abdomen  ends 


48  STUDIES    OF   ANIMAL   TYPES 

in  forked  stylets.  Attached  to  each  side  of  the  first  ab- 
dominal segment  of  the  females  will  often  be  found  a  sack 
of  eggs. 

Make  a  drawing  showing  all  these  points. 

B.  CYPRIS.     It  is  usually  found  with  cyclops  but  differs 
from  most  crustaceans  in  having  a  bivalved  shell.     It  is 
often  mistaken  for  a  mollusk.    The  shell  is  really  composed 
of  the  carapace,  which  is  divided  into  two  parts.   The  halves 
are  hinged  along  the  dorsal  edge  like  the  valves  of  a  clam. 
Within  the  shell  are  seven  distinct  pairs  of  appendages 
which  betray  the  family  connections  of  this  little  animal. 

C.  DAPHNIA.     Sometimes  the  aquarium  is  alive  with 
these  grotesque,  hump-backed  crustaceans  that  travel  with 
a  jerky  motion  like  cyclops.     The  whole  body  is  covered 
with  the  carapace.     The  head  is  drawn  down,  and  the  back 
is  humped  up  like  a  stooping,  round-shouldered  man.     The 
antennae  are  long  and  are  thrown  out  in  front.     Note  the 
five  pairs  of  leaf  like  swimming  feet. 

D.  CRABS.     If  possible,  get  a  rock  crab  for  the  collec- 
tion.    Compare  it  with  the    crayfish.     Note  the    greatly 
broadened  carapace.     Note  the  abdomen,  which  is  curled 
beneath   the   cephalothorax  and  is   permanently   carried 
there.     Compare  the  antenna?  and  the  antennules  with 
those  of  the  lobster. 

HERMIT  CRAB.  If  one  of  these  is  in  the  collection,  note 
the  soft  abdomen.  Why  does  this  crab  need  a  shell,  and 
the  rock  crab  not? 

XVI.  —  THE  LOCUST,  OR  GRASSHOPPER 

Materials.  —  Specimens  of  locusts  alive  and  preserved,  glass  slides, 
cover  glasses,  compound  microscope,  glass  bell  jar,  dissecting  pan, 
pins,  dissecting  instruments, 


THE  LOCUST,  OR  GRASSHOPPER  49 

Directions.  —  (For  the  field  work,  the  Carolina  locust  will  serve 
as  well,  if  not  better,  than  any  other  species ;  but  wherever  the 
American  locust  is  available  it  will  be  found  better  for  dissection 
because  it  is  much  larger.  The  Carolina  locust  has  dark  hind  wings 
with  yellow  borders,  is  found  along  the  roadsides,  and  is  dusty- 
gray  in  color.  The  American  locust  is  considerably  larger  and  has 
nearly  transparent  hind  wings. 

An  abundant  supply  of  specimens  may  be  caught  with  a  net  and 
preserved  in  eighty-five  per  cent  alcohol,  but  fresh  specimens  are 
more  desirable  for  dissection.  Care  should  be  exercised  to  get 
both  males  and  females  for  comparison  and  the  nymphs  in  all 
stages  of  development.  The  nymphs  may  be  recognized  from 
their  lack  of  fully  developed  wings.) 

A.  FIELD  STUDY  OF  THE  LOCUST.    Study  the  Carolina 
locust  in  the  field.     Where  are  they  found?    Watch  and 
describe  their  habits  of  flight.     How  far  do  they  usually 
fly?    Do  they  make  any  noise  during  flight?    Are  they 
easily  seen  after  they  alight?    Why  is  this?    What  color 
are  they  ?    What  kind  of  places  do  they  usually  choose  to 
alight  upon  ?    Have  they  any  method  of  locomotion  other 
than  that  of  flight  ?    When  are  they  most  active  ?    Deter- 
mine by  observing  them  on  warm  and  cool  days  and  on 
frosty  mornings  and  at  noontide.     What  effect  then  has 
temperature  upon  their  activities  ?   Have  they  any  enemies  ? 
How  are  they  protected  from  their  enemies  ? 

B.  STUDY  OF  A  LIVING  LOCUST.    Place  the  locust  under 
a  large  glass  jar  and  note  its  manner  of  walking.     Note  the 
positions  of  the  legs  in  the  succeeding  phases  of  walking. 
How  many  legs  has  the  locust?    Note  their  variation  in 
size.    Allow  one  to  go  free,  and  note  what  legs  are  used 
in  leaping.     How  far  can  it  jump  ? 

Note  the  respiratory  movements  of  the  abdomen.  Count 
the  number  per  minute.  Does  it  vary  in  different  indi- 

HERRICK  LAB.  EX.  —  4 


50  STUDIES   OF   ANIMAL   TYPES 

viduals  or  under  excitement?  Withhold  food  for  half  a 
day  from  a  specimen  and  then  offer  it  fresh  clover  or  lettuce 
leaves  and  note  its  manner  of  eating. 

C.  EXTERNAL  FEATURES.  Note  that  the  body  is  com- 
posed of  three  great  divisions:  head,  thorax,  and  abdomen. 
Is  the  abdomen  similar  in  any  way  to  the  body  of  an  earth- 
worm ?  Examine  the  thorax  and  note  that,  like  the  abdo- 
men, it  is  divided  into  segments,  but  that  the  division  lines 
are  not  so  plain  as  on  the  abdomen.  The  head  is  ap- 
parently not  segmented.  Actually  it  is  composed  of  several 
segments  so  closely  grown  together  that  it  is  impossible  to 
distinguish  them. 

The  head  end  of  the  body  is  known  as  the  anterior  end, 
while  the  opposite  end  is  called  the  posterior  end.  When 
the  animal  is  in  its  normal  position  for  locomotion  on  the 
ground,  the  side  of  the  body  next  to  the  ground  is  known 
as  the  ventral  side,  while  the  opposite  side,  or  back,  is  called 
the  dorsal  side. 

Note  that  the  right  and  left  sides  of  the  body  of  the 
locust  are  alike.  That  is,  this  animal  is  bilaterally  sym- 
metrical. This  form  of  structure  is  characteristic  of  those 
animals  that  move  swiftly. 

Head.  —  Note  the  two  large  compound  eyes.  Tear  off  a 
piece  of  the  eye  and  mount  on  a  slide  in  water  beneath  a 
cover  glass.  Examine  with  the  low-power  objective.  How 
does  it  appear  ? 

Make  a  drawing  of  twelve  of  the  hexagonal  divisions. 
Each  one  of  these  divisions  corresponds  to  a  simple  eye, 
and  all  of  them  taken  together  constitute  a  compound  eye. 

Note  the  round  simple  eye,  or  ocellus,  in  a  groove  in  the 
middle  of  the  forehead.  Note  a  simple  eye  at  the  upper, 
inside  corner  of  each  compound  eye. 


THE   LOCUST,   OR   GRASSHOPPER  51 

Note  two  long  slender  appendages  on  the  head.  Are 
they  segmented  ?  These  are  the  antennce,  or  feelers.  Pull 
one  off  close  to  the  head,  mount  it  under  the  microscope, 
and  count  the  segments. 

Make  a  drawing  of  one. 

Note  the  broad,  notched  flap  at  the  lower  end  of  the  face. 
Lift  it  up  and  detach.  This  is  the  upper  lip,  or  labrum. 

Make  a  drawing  of  it. 

Just  beneath  this,  note  two  hard  black  bodies.  These 
are  the  mandibles.  Detach  them  both.  Note  the  tooth- 
like  projections  on  the  inside  edges. 

Make  a  drawing  of  both. 

Beneath  the  mandibles,  note  two  maxillce.  Each  one 
consists  of  several  pieces.  Each  also  bears  a  slender,  seg- 
mented appendage  called  a  palpus.  The  (two  palpi  are 
known  as  the  maxillary  palpi. 

Make  a  drawing  of  each. 

Lastly,  note  the  under  lip,  or  labium.  It  bears  two 
slender,  segmented  appendages,  the  palpi,  similar  to  those 
of  the  maxillae.  Do  they  have  the  same  number  of  seg- 
ments ?  They  are  called  the  labial  palpi. 

Make  a  drawing  of  the  labium,  with  its  palpi. 

Thorax.  —  Note  that  this  part  of  the  body  is  composed  of 
three  divisions,  or  segments.  They  may  be  easily  seen  on 
the  under  side,  because  each  one  bears  a  pair  of  legs.  The 
segment  next  to  the  head  is  called  the  prothorax.  The  next 
is  called  the  mesothorax,  and  the  last,  the  metathorax.  The 
mesothorax  and  metathorax  each  bear  a  pair  of  wings. 

How  many  wings  are  there  ?  Where  are  the  hind  wings 
carried  ?  Are  they  expanded  or  folded  ?  Detach  all  wings. 
What  is  the  relative  size  of  the  two  pairs?  How  do  the 
hind  wings'  differ  from  the  front  ones  ? 


52  STUDIES   OF  ANIMAL  TYPES 

Make  a  drawing  of  a  front  wing  and  a  hind  wing. 

Detach  a  front  leg.  Note  that  it  is  composed  of  segments 
of  unequal  length.  The  first  one  is  called  the  coxa.  It  is 
short  and  globular.  The  second  segment  is  the  trochanter, 
the  third  femur,  fourth  tibia,  and  the  remaining  ones  are 
called  the  tarsal  segments.  The  last  tarsal  segment  bears 
a  pair  of  claws. 

Make  a  drawing  of  a  leg. 

Abdomen.  —  Note  that  between  the  segments  is  soft, 
flexible  skin,  which  furnishes  freedom  for  movement.  Note 
that  the  skin  of  the  segments  is  hard  and  smooth.  This  is 
due  to  a  hard  horny  substance  called  chitin  that  is  deposited 
in  the  skin.  On  each  side  of  the  first  segment  is  an  oval 
transparent  membrane  that  constitutes  the  ear  of  the  insect. 

On  each  side  of  each  segment,  near  the  front  margin,  will 
be  seen  a  small  aperture.  These  are  the  openings,  termed 
spiracles,  through  which  the  insect  takes  in  air. 

The  last  segments  bear  in  the  female  two  pairs  of  strong 
curved  organs.  These  compose  the  ovipositor.  They  are 
used  to  make  holes  in  the  ground  in  which  to  lay  the  eggs. 
The  end  of  the  abdomen  of  the  male  is  blunt  and  rounded, 
and  bears  three  inconspicuous  appendages. 

D.  INTERNAL  FEATURES.  With  head  directed  from  you, 
pin  a  freshly  killed  female  locust  on  its  ventral  surface  in  a 
dissecting  pan,  by  spreading  the  wings  and  pinning  them 
securely  to  -the  wax  or  cork.  Run  a  pin  through  the 
posterior  end  of  the  abdomen  into  the  cork.  With  a  pair 
of  scissors  cut  carefully,  from  the  ovipositor  to  the  head, 
just  through  the  skin,  on  the  dorsal  side,  a  little  to  the  left 
of  a  median  line.  With  a  forceps  lift  away  the  skin  on  the 
right  of  the  slit  and  note  the  delicate,  whitish  blood  vessel, 
the  heart.  Where  does  the  heart  lie?  How  long  is  it? 


THE  LOCUST,  OR  GRASSHOPPER  53 

Does  it  extend  outside  of  the  abdomen  ?  It  will  take  care- 
ful dissection  to  find  the  heart  and  not  injure  it.  Often  it 
may  be  seen  best  by  dissecting  the  abdomen  from  the 
ventral  side.  Now  cut  along  the  right  of  the  median  line, 
parallel. with  the  first  slit,  and  lift  away  the  skin  from  the 
roof  of  the  abdomen. 

Note  the  white,  silvery  air  tubes  (trachece)  (page  161  of 
the  text)  ramifying  throughout  the  body.  Note  the  large 
longitudinal  tracheae  running  along  the  sides  of  the  abdo- 
men. How  are  these  connected  with  the  spiracles? 

Make  a  diagram  of  the  tracheal  system  showing  the  con- 
nection with  the  spiracles. 

Mount  some  of  the  trachea?  under  a  microscope  and  note 
their  appearance.  A  spiral  elastic  fiber  is  coiled  inside  the 
wall  of  each  tube  to  hold  it  open. 

Make  a  drawing  of  a  piece  of  a  trachea. 

There  are  usually  two  masses  of  yellowish,  cylindrical 
eggs  in  the  abdomen  of  the  female.  The  eggs  are  piled 
in  tiers  on  the  sides  and  top  of  the  alimentary  canal.  Note 
a  white  tube,  the  oviduct,  running  posteriorly  from  each  egg 
mass  to  the  ventral  side  of  the  abdomen.  Here  the  two 
oviducts  unite  and  form  a  tube,  the  vagina,  which  opens  to 
the  outside  between  the  ovipositors. 

Remove  the  egg  masses  and  note  the  long,  straight  ali- 
mentary canal,  running  from  the  head  to  the  posterior  end 
of  the  body.  Begin  at  the  mouth  and  trace  it,  noting  the 
following  parts :  — 

The  esophagus,  or  gullet,  which  runs  from  the  mouth 
upward  through  the  head  and  then  posteriorly  into  the 
thorax. 

In  the  thorax  the  esophagus  enlarges  into  a  large  food 
reservoir,  the  crop,  in  which  the  food  is  held  for  a  time 


54  STUDIES    OF   ANIMAL   TYPES 

and  ground  up,  as  it  were,  into  fine  bits.  Note  the 
delicate,  white  salivary  glands,  one  on  each  side  of  the 
crop.  They  connect  with  the  mouth  by  means  of  two 
salivary  ducts. 

Succeeding  the  crop,  but  not  distinctly  separated  from  it, 
is  the  proventriculus,  or  gizzard.  Like  that  of  a  chicken, 
the  locust's  gizzard  has  thick,  muscular  walls  for  com- 
minuting the  food.  At  the  posterior  end  of  the  gizzard 
there  is  a  circle  of  rather  large,  conspicuous  appendages, 
the  gastric  cceca.  Note  their  shape,  number,  and  manner  of 
attachment  to  the  alimentary  canal.  Their  function  is  to 
secrete  a  digestive  fluid. 

Succeeding  the  gizzard  is  the  stomach,  or  ventriculus.  It 
is  not  sharply  differentiated  from  the  other  parts  of  the  ali- 
mentary canal  adjacent  to  it.  Several  long  slender  tubules 
arise  from  the  posterior  end  of  the  stomach  and  float  free 
in  the  body  cavity.  These  are  the  Malpighian  vessels  (page 
163  of  the  text).  They  take  up  impurities  from  the  blood 
and  carry  them  off  through  the  intestine.  Their  action  is 
urinary,  similar  to  the  kidneys  of  the  higher  animals. 

The  remainder  of  the  alimentary  canal  is  the  intestine. 

Make  a  drawing  of  the  alimentary  canal  showing  all  the 
parts  spoken  of  above. 

Trace  the  course  of  the  food  from  the  time  it  enters  the 
mouth,  and  show  how  it  is  acted  on  in  the  different  organs 
of  the  digestive  system.  After  the  food  leaves  the  stomach 
its  nutritive  portion  is  absorbed  directly  through  the  walls 
of  the  intestine  by  the  blood,  which  carries  it  to  all  parts  of 
the  body. 

Remove  the  alimentary  canal. 

Note  a  double,  white  cord  running  along  the  floor  of  the 
body  cavity.  Note  that  these  two  threads  are  connected 


THE    CABBAGE    BUTTERFLY  55 

in  many  of  the  segments  by  a  double  knot,  or  ganglia.  Note 
the  smaller  nerves  that  are  given  off  from  each  pair  of 
ganglia.  Trace  the  double  cord  to  the  head.  Note  that 
the  cords  separate,  one  cord  passing  up  the  right  side  of 
the  esophagus  and  one  up  the  left  side.  Note  also  that 
the  cords  join  again  on  top  of  the  esophagus  and  that  each 
one  is  enlarged  at  the  end  to  form  a  large  double  ganglion, 
the  brain. 

Make  a  diagram  of  the  nervous  system. 

E.  TOPICS  FOR  FURTHER  STUDY.  Make  a  summary  of 
the  points  to  be  drawn  from  this  exercise;  namely,  the 
habits,  habitats,  food,  and  movements  of  the  locust,  the 
divisions  of  the  body,  number  and  kinds  of  eyes,  number  of 
legs,  antennae  and  wings,  the  breathing  organs,  digestive 
organs,  circulatory  organs,  and  organs  of  excretion.  Fix 
in  the  mind  the  position  of  this  insect  in  the  animal  king- 
dom. To  what  branch,  class,  order,  family,  genus,  and 
species  does  it  belong  ?  Compare  it  with  other  members 
of  the  Arthropoda;  namely,  spiders,  lobsters,  centipeds, 
and  insects.  Make  a  summary  of  its  leading  characteristics. 

XVII.  —  THE  CABBAGE  BUTTERFLY 

Materials.  —  Specimens  of  cabbage  butterfly,  camel's  hair  brush, 
alcohol,  glass  slides,  cover  glasses,  compound  microscope,  hydro- 
chloric acid,  hypochlorite  of  sodium,  carbolic  acid  crystals,  oil  of 
turpentine,  Canada  balsam. 

Directions.  —  (The  large  milkweed  butterfly,  or  the  white  cab- 
bage butterfly  will  answer  for  this  exercise.  The  milkweed  butterfly 
is  also  known  as  the  Monarch,  and  is  figured  in  the  text.) 

A.  EXTERNAL  FEATURES.  Observe  the  divisions  of  the 
body.  Do  they  correspond  to  those  of  the  locust?  What 


56  STUDIES    OF   ANIMAL   TYPES 

is  found  all  over  the  body  ?  Were  the  same  structures  found 
on  the  body  of  the  locust? 

Note  the  two  large  compound  eyes.  With  a  camel's  hair 
brush,  carefully  remove  the  scales  from  the  head.  Are 
there  any  simple  eyes?  There  is  no  movable  flaplike 
labrum  as  in  the  locust.  The  labrum  is  small,  narrow,  and 
runs  transversely  across  the  head.  It  bears  at  each  end  a 
tuft  of  fine  hairs.  Note  that  there  are  no  mandibles.  Note 
that  there  is  a  long  proboscis  coiled  up  beneath  the  "  chin." 
This  is  made  up  of  the  two  maxillce,  grooved  on  the  inner 
sides  and  joined  together  to  form  a  tube.  If  the  specimen 
is  fresh,  the  tube  may  be  uncoiled.  If  it  is  dry  or  has  been 
in  alcohol,  soak  the  head  in  warm  wTater  until  it  is  soft. 
The  under  lip,  or  labium,  is  also  immovable  and  forms  the 
under  side  of  the  head.  Note  the  two  hairy  projections 
pointing  upward  in  front  of  the  head.  These  come  from 
the  labium  and  are  the  labial  palpi.  Compare  the  antennae 
with  those  of  the  locust.  Are  they  segmented?  What  is 
the  shape  of  the  antennae  at  the  ends  ?  This  shape  is  char- 
acteristic of  the  butterflies. 

Make  a  drawing  of  a  side  view  of  the  head  showing  as 
many  of  the  above  points  as  possible. 

How  many  wings  has  the  butterfly  ?  How  do  they  differ 
from  those  of  the  locust?  Are  they  folded  at  any  time? 
How  are  they  held  when  the  insect  is  at  rest?  To  deter- 
mine this,  living  specimens  must  be  observed  in  the  field. 
Brush  off  some  of  the  scales  and  mount  them  in  alcohol. 
Examine  with  the  low-power  objective  and  note  the 
shape.  Note  that  the  scales  differ  considerably  in  size 
and  shape.  All  gradations  may  be  found  from  hairs  to 
flat  scales.  In  fact,  the  scales  are  modified  hairs.  Note 
the  longitudinal  ridges,  or  strice.  Note  the  small  pro- 


THE    CABBAGE    BUTTERFLY  57 

jection,  or  handle,  by  which  the  scales  are  attached  to 
the  wing  membrane.  Examine  the  wing  where  the  scales 
were  removed,  and  note  the  manner  in  which  the  scales 
were  laid  on  the  wing.  With  a  brush,  carefully  remove  all 
the  scales  from  the  wing,  both  above  and  below.  Better 
still,  dip  the  wings  in  alcohol,  then  immerse  them  for  a 
minute  in  dilute  hydrochloric  acid  (one  part  acid  to  nine 
parts  water),  and  then  place  them  in  Labaraque  solution 
(hypochlorite  of  sodium),  until  clear  and  transparent. 
Finally  place  them  in  alcohol  again  until  they  rise  and  float. 
Then  mount  them  in  alcohol  for  immediate  study. 

(If  it  is  desired  to  make  a  permanent  mount  one  should  proceed 
as  follows :  Transfer  the  wing  from  the  alcohol  to  a  clearing  mixture 
(two  parts  by  weight  of  carbolic  acid  crystals  and  three  parts  of 
rectified  oil  of  turpentine)  and  allow  it  to  remain  there  ten  minutes. 
Finally  transfer  it,  together  with  some  of  the  clearing  mixture,  to 
a  glass  slip,  put  some  Canada  balsam  on  top,  and  cover  with  a  cover* 


Note  that  the  wing  is  transparent.  Observe  the  veins 
running  lengthwise  of  the  wing.  Note  the  few  cross 
veins. 

Make  a  drawing  of  the  right  front  and  hind  wings  show- 
ing all  the  veins  in  each. 

How  many  legs  has  the  butterfly?  Note  that  each  one 
is  divided  into  segments.  Make  out.  each  segment,  coxa, 
trochanter,  femur,  tibia,  and  tarsi. 

Make  a  drawing  of  the  leg. 

Observe  the  difference  in  shape  of  the  thorax  from  that 
of  the  locust. 

Make  a  drawing  of  a  side  view  of  the  abdomen. 

B.  THE  LIFE  HISTORY  OF  THE  CABBAGE  BUTTERFLY. 
The  life  history  may  be  followed  on  cabbage  plants  in  the 


58  STUDIES    OF   ANIMAL   TYPES 

field  or  plants  may  be  grown  in  the  house  for  the  cater- 
pillars to  eat. 

The  eggs  are  laid  throughout  the  summer  on  the  leaves  of 
cabbage.  Obtain  some,  if  possible,  and  see  how  long  it  takes 
for  them  to  hatch.  The  eggs  are  nearly  white,  conical,  and 
ribbed.  They  are  large  enough  to  be  easily  seen  with  the 
unaided  eye  and  are  usually  to  be  found  in  abundance.  If 
the  eggs  cannot  be  obtained,  the  pale  green  caterpillars  may 
be  found  eating  the  leaves  and  can  be  easily  fed  indoors. 
They  will  grow  rapidly.  Observe  the  number  of  times  they 
molt.  In  two  or  three  weeks  each  one  will  change  to  a 
pupa.  The  pupa  is  known  as  a  chrysalis.  What  color  is 
it  ?  Where  is  it  placed  and  in  what"  position  ?  How  is  it 
attached  to  the  leaf?  Watch  the  chrysalis  and  see  how 
long  before  the  adult  appears.  How  does  the  adult  get  out 
of  the  chrysalis  ? 

Watch  all  these  stages  and  make  notes  on  all  the  changes 
and  the  time  occupied  in  each  stage. 

From  this  study  of  the  life  history  of  the  cabbage  butter- 
fly, it  is  evident  that  it  passes  through  remarkable  and 
distinct  changes  from  the  egg  to  the  adult.  In  fact,  there 
are  four  distinct  stages  in  the  life  history  of  this  butterfly ; 
namely,  the  egg,  larva,  pupa,  and  adult.  An  insect  that 
passes  through  such  a  series  of  distinct  changes  is  said  to 
have  a  complete  metamorphosis. 

C.  TOPICS  FOR  FURTHER  STUDY.  Give  a  summary  of 
the  life  history  of  the  butterfly.  Give  the  characteristics 
of  its  wings.  Compare  its  mouth  parts  with  those  of  the 
locust.  Make  a  diagrammatic  drawing  of  its  body  to  show 
the  three  regions.  Find  out  to  what  order  it  belongs. 
Make  a  list  of  other  insects  belonging  to  the  same  order. 
What  is  characteristic  of  all  these  insects  ? 


THE  SQUASH  BUG  AND  THE  HARLEQUIN  CABBAGE  BUG   59 


XVIII.  —  THE  MOUTH  PARTS  AND  LIFE  HISTORY  OF  THE 
SQUASH  BUG  AND  THE  HARLEQUIN  CABBAGE  BUG 

Materials.  —  Squash  bugs  and  harlequin  cabbage  bugs,  magnifier, 
potassium  hydrate,  pins. 

Directions.  —  (The  squash  bug  is  an  ill-smelling,  dark-brown 
insect  a  little  less  than  £  of  an  inch  in  length.  It  is  common  in  gar- 
dens on  squashes,  melons,  and  cucumbers,  and  the  adults  may  be 
easily  secured  during  the  summer.  They  should  be  placed  in  al- 
cohol or  formalin. 

In  the  Southern  states  the  harlequin  cabbage  bug  may  be  used 
instead.  This  bug  is  known  as  the  "calico  back,"  or  "terrapin 
bug,"  and  is  very  injurious  to  cabbages,  radishes,  and  mustard. 

Better  than  either  of  these,  for  a  study  of  the  mouth  parts,  is  the 
dog-day  harvest  fly,  or  cicada.) 

A.  EXTERNAL  FEATURES.  Head.  —  Note  the  compound 
eyes.  They  are  not  so  large  as  those  of  the  locust  or  but- 
terfly. Note  the  simple  eyes.  How  many  are  there  and 
where  are  they  ?  Note  the  antennae.  How  many  segments 
in  each  one  ?  How  do  they  differ  from  those  of  the  butter- 
fly ?  Note  that  the  head  slopes  greatly  in  front. 

Mouth  parts.  —  Note  a  sharp  pointed,  immovable,  upper 
lip.  At  the  base  of  this  arises  a  slender  beak  that  is  found 
pointing  backward  beneath  the  thorax  between  the  bases 
of  the  legs.  Take  off  the  head  and  mount  it  on  a  slender 
pin,  which  can  then  be  stuck  into  a  piece  of  cork  to  facilitate 
handling.  Examine  the  beak  with  the  low  objective  or  a 
hand  lens.  Is  it  jointed  ?  How  many  segments  are  there  ? 
With  sharp  pointed  needles  pick  the  beak  apart.  Fresh 
specimens  or  those  preserved  in  alcohol  may  be  used,  but 
better  than  either  are  dried  specimens,  the  heads  of  which 


60  STUDIES    OF   ANIMAL   TYPES 

have  been  boiled  in  potassium  hydrate  (KOH)  until  they 
are  soft.  How  many  bristles  are  in  the  beak?  The  part 
of  the  beak  in  which  they  are  inclosed  is  supposed  to  be 
the  lower  lip  and  labial  palpi  grown  together.  These  form 
a  sheath  to  inclose  the  bristlelike  mandibles  and  maxillae. 
Note  the  groove  on  top  of  the  lower  lip  in  which  the  bristles 
lie. 

Make  a  drawing  of  the  mouth  parts. 

Recall  the  structure  of  the  mouth  of  a  grasshopper  and 
the  manner  in  which  that  insect  obtains  its  food.  The 
squash  bug  obtains  its  food  by  inserting  its  beak  into  the 
tissues  of  the  leaves  and  sucking  up  the  juices.  What 
can  you  say  in  regard  to  the  adaptations  of  the  mouth 
parts  of  the  grasshopper  and  of  the  squash  bug  to  their 
different  functions? 

B.  LIFE  HISTORY  OF  THE  SQUASH  BUG.  The  adult 
insect  lives  over  the  winter  in  crevices  or  beneath  boards 
or  rubbish,  and  early  in  the  spring  lays  the  eggs  in  irregu- 
lar clusters,  usually  on  the  under  sides  of  the  leaves  of 
squashes,  melons,  and  cucumbers.  The  eggs  are  dark 
yellow-brown,  with  a  glossy  surface,  and  are  plainly  visi- 
ble to  the  unaided  eye.  Are  the  clusters  of  eggs  equal  in 
size?  How  many  eggs  in  one  cluster?  Are  the  eggs 
ever  laid  singly? 

The  eggs  may  be  brought  into  the  laboratory  and  placed 
on  squash  plants  in  breeding  cages.  It  would  be  more  satis- 
factory, perhaps,  to  take  a  breeding  cage  to  the  field  or 
garden  and  place  it  over  a  plant  and  watch  the  life  history 
of  the  insect  there.  It  may  lend  interest  to  allow  the  pupils 
to  watch  the  life  history  of  this  insect  in  their  own  home 
gardens.  Note  the  length  of  time  it  takes  the  eggs  to  hatch. 
Compare  a  young  nymph  with  an  adult,  and  note  the  differ- 


THE   COMMON   AND   MALARIAL   MOSQUITOES  61 

ences.  Note  the  number  of  times  that  the  nymphs  molt. 
Note  the  process  of  molting.  How  long  does  it  take  the 
nymphs  to  be  come  adults  ? 

Note  that  the  young  squash  bugs  resemble  the  adults. 
What  do  the* adults  have  that  the  nymphs  lack?  From 
this  study  of  life  history,  it  will  be  seen  that  the  squash 
bugs  do  not  pass  through  any  remarkable  or  distinct  changes, 
for  the  young  resemble  the  adults.  Such  insects  are  said 
to  have  an  incomplete  metamorphosis.  How  does  this  com- 
pare with  the  butterfly? 

The  harlequin  cabbage  bug  has  an  incomplete  meta- 
morphosis also. 

To  what  order  do  these  insects  belong  ?  Find  out  what 
other  insects  belong  to  the  same  order.  All  of  them  have 
an  incomplete  metamorphosis. 

The  harlequin  cabbage  bug  lays  its  barrel-shaped  eggs 
on  the  leaves  of  mustard,  turnips,  cabbage,  etc.  The  life 
history  of  this  insect  may  be  very  easily  followed  in  the 
garden  or  in  the  laboratory.  The  eggs  are  conspicuous 
and  easily  found. 

C.  TOPICS  FOR  FURTHER  STUDY.  Write  out  a  summary 
of  the  life  history  of  the  insect  studied,  giving  all  the 
changes.  Write  a  list  of  the  food  plants  of  the  insect. 
Fix  firmly  in  mind  the  mouth  parts  and  the  manner  in 
which  these  insects  obtain  their  food.  Compare  with  the 
grasshopper.  Bear  in  mind  the  kind  of  metamorphosis  pos- 
sessed by  these  bugs  and  the  order  to  which  they  belong. 

XIX.  —  THE  COMMON  AND  MALARIAL  MOSQUITOES 

Materials.  —  Eggs  and  adults  of  common  mosquito  (Culex)  and 
malarial  mosquito  (Anopheles),  glass  jars,  pond  scum,  watch  glasses, 
magnifiers,  glass  slides,  cover  glasses,  compound  microscope. 


62  STUDIES  OF  ANIMAL  TYPES 

Directions.  —  A.  LIFE  HISTORY  OF  CULEX.  The  com- 
mon mosquito  lays  its  eggs  in  summer,  in  boat-shaped 
masses,  on  the  surface  of  the  water  in  rain  tubs,  ditches, 
etc.  The  egg  masses  are  plainly  visible  to  the  unaided 
eye  and  appear  like  small  patches  of  soot  floating  on  the 
water.  Find  some,  take  them  into  the  laboratory,  and  place 
them  on  water  in  some  kind  of  a  jar.  Note  the  shape  of  the 
egg  mass.  Which  side  of  the  mass  is  concave  and  which 
side  is  convex  ?  Can  the  individual  eggs  be  seen  with  the 
naked  eye  ?  Note  that  the  egg  masses  appear  to  be  sur- 
rounded by  a  glistening  film  on  the  under  sides.  This  is 
due  to  a  layer  of  air  about  them.  Push  the  mass 
beneath  the  water.  Does  it  sink?  Does  it  get  wet? 
Break  up  an  egg  mass  and  examine  the  individual  eggs 
under  the  microscope.  What  is  the  shape  of  an  egg? 
The  wiggler  emerges  from  the  larger  end  of  the  egg. 
On  which  end  do  the  eggs  stand  when  floating  in  the 
mass?  Why? 

Make  a  drawing  of  the  egg  mass  and  of  a  single  egg. 

In  a  day  or  two,  if  the  room  is  warm,  the  eggs  in  the  jar 
will  have  hatched.  Note  the  length  of  time  it  took  them 
to  hatch  after  being  brought  into  the  house.  Take  out  some 
of  the  young  larva?  and  examine  them  beneath  the  micro- 
scope. It  will  be  well  to  put  some  cotton  fibers  under  the 
cover  glass  to  entangle  the  wigglers,  in  order  to  keep 
them  in  the  field  of  vision.  Note  the  transparent  body 
divided  into  head,  thorax,  and  abdomen.  Note  the  two 
dark  spots,  eyes,  on  the  head.  Note  the  two  antennae  with 
bristles  on  the  ends.  Note  the  bunches  of  dark  hairs  on 
the  head  near  the  mouth.  Is  the  thorax  any  larger  than 
the  abdomen?  Count  the  segments  in  the  abdomen. 
On  the  caudal  end  of  the  abdomen  note  the  long  tube. 


THE    COMMON    AND    MALARIAL   MOSQUITOES  63 

This  is  the  breathing  tube.  Note  beside  it  a  cylindrical 
segment  (the  last)  of  the  abdomen,  bearing  on  its  free  end 
some  long  bristles  and  four  flaps.  The  flaps  function  as 
swimming  organs  and  also,  to  some  extent,  as  respiratory 
organs.  Note  the  long  bristles  along  the  sides  of  the  thorax 
and  abdomen.  Are  they  branched?  Note  the  tracheae 
leading  from  the  breathing  tube  and  running  throughout 
the  length  of  the  body  to  the  head.  Are  there  any  side 
and  cross  branches  from  the  two  main  tubes  ? 

Make  a  drawing  of  the  larva  showing  all  these  points. 

To  furnish  food  for  the  wiggle r  put  some  pond  scum 
into  the  jar.  They  ought  to  grow  fast  enough  in  a 
warm  room  to  become  plainly  visible  at  the  end  of  two 
or  three  days.  Watch  them  carefully  in  the  water.  What 
position  do  they  occupy?  Why?  Look  at  the  head  and 
note  the  movements  of  the  two  dark  bunches  of  hair  noted 
above.  They  create  currents  of  water  to  bring  food  to 
the  animal.  Do  the  larvse  remain  at  the  top  of  the 
water  all  the  time?  How  do  they  get  to  the  bottom? 
Watch  one  come  to  the  surface.  Is  there  any  difference 
between  its  descent  and  ascent?  Is  it  lighter  or  heavier 
than  water?  How  does  the  thorax  compare  in  size  with 
the  abdomen? 

Make  a  drawing  of  a  large  wiggler. 

Watch  the  larvae  carefully  every  day  and  note  any  changes 
that  may  take  place  in  them.  At  the  end  of  six  to  fourteen 
days  dark-colored  objects  ought  to  appear  in  the  jars,  each 
with  a  large  anterior  end  and  a  slender  abdomen.  These 
are  the  pupce  to  which  the  larvse  have  transformed.  Are 
the  pupae  active  ?  Look  closely  and  note  the  two  tubes  on 
top  of  the  thorax.  These  are  the  breathing  tubes.  Re- 
call the  position  and  number  of  the  breathing  tubes  of  the 


64  STUDIES    OF   ANIMAL   TYPES 

larva.  Do  the  pupae  seem  to  take  food  ?  As  a  matter  of 
fact,  they  do  not.  Note  the  exact  time  it  took  a  larva  to 
transform  to  a  pupa. 

Make  a  drawing. of  a  pupa. 

B.  STUDY  OF  ADULT  CULEX.  As  soon  as  pupae  are  noted, 
the  top  of  the  jar  should  be  covered  with  mosquito  netting 
to  prevent  the  escape  of  the  adults.  Note  the  time  the  pupae 
exist  before  transforming  to  adults.  Catch  as  many  adults 
as  possible  in  cyanide  bottles,  mount  them  very  carefully 
on  the  points  of  small  pins  by  sticking  them  into  the  under 
side  of  the  thorax.  In  this  way  the  insects  may  be  handled 
without  fear  of  ruining  them.  With  the  hand  lens,  note 
the  compound  eyes.  Note  the  two  antennae.  Examine 
several  specimens  and  determine  whether  there  is  any 
difference  in  the  antennae  of  different  individuals.  The 
males  have  antennae  bearing  very  many  long  hairs,  while 
the  females  have  antennae  bearing  few  short  hairs.  In 
addition  to  the  antennae,  the  head  of  the  male  bears  two 
long,  jointed,  and  hairy  appendages  termed  the  palpi. 
The  hairy  palpi  and  antennae  give  the  head  of  the  male  a 
characteristic  appearance,  which  at  once  distinguishes  this 
sex  from  the  female.  Examine  several  specimens  until 
there  is  no  difficulty  in  telling  one  sex  from  the  other. 
The  male  does  not  bite.  Note  the  single  prominent  pro- 
jection from  the  head  of  the  female.  This  is  the  proboscis. 
Note  that  there  are  two  very  short  projections  on  the 
head  at  the  base  of  the  proboscis.  These  are  the  palpi. 

How  many  wings  has  an  adult  mosquito  ?  How  does  the 
number  compare  with  that  of  the  butterfly?  Note  the 
pair  of  knobbed  threads  borne  by  the  metathorax  in  place 
of  the  second  pair  of  wings  borne  by  locusts  and  butterflies. 
Mount  a  wing  in  water  on  a  slide.  Note  the  longitudinal 


THE    COMMON   AND   MALARIAL   MOSQUITOES  65 

veins.  Does  the  wing  bear  any  scales?  Where  are  the 
scales  borne  ?  How  does  this  compare  with  the  wing  of  a 
butterfly?  With  the  wing  of  a  locust?  Note  the  shape 
of  the  wing. 

Make  a  drawing  of  a  wing  showing  the  veins  and  scales. 

Draw  the  heads  of  male  and  female  with  appendages. 

Note  that  the  body  is  clothed  with  scales.  Note  the  long, 
slim  abdomen.  How  many  legs  has  the  mosquito  ?  How 
do  they  differ  from  those  of  the  grasshopper  ? 

C.  STUDY  OF  THE  MALARIAL  MOSQUITO,  ANOPHELES. 
Malarial  mosquitoes  usually  breed  in  ditches,  in  road- 
side pools  of  water,  or  in  other  clear  pools,  seldom,  if  ever, 
in  foul  pools.  The  larvae  of  Anopheles  lie  horizontally 
just  beneath  the  surface  film.  They  may  be  collected  and 
the  adults  reared  in  the  same  manner  as  those  of  Culex. 

Compare  the  positions,  habits,  and  movements  of  the 
larvae  with  those  of  Culex.  Note  that  the  head  of  the  Ano- 
pheles larva  is  turned  half  way  round  when  the  larva  is 
feeding.  Note  how  quickly  the  head  is  turned  to  its  normal 
position  when  the  larva  stops  feeding.  Do  the  larvae  have 
any  markings  on  the  abdomen?  How  long  before  they 
transform  to  pupae?  How  do  the  pupae  differ  from  those 
of  Culex?  Note  the  short,  wide,  respiratory  tubes.  How 
long  before  the  pupae  transform  to  adults  ? 

Compare  an  adult  female  with  an  adult  female  Culex. 
Compare  the  heads  of  the  two  females.  How  many  ap- 
pendages on  the  head  of  the  Anopheles?  How  many  on 
the  head  of  Culex  that  are  conspicuous?  Compare  the 
positions  assumed  by  the  adults  of  Anopheles  and  Culex 
when  they  alight  on  the  side  and  top  walls  of  the  cages. 
Make  a  summary  of  all  the  differences  between  the  larvae, 
pupae,  and  adult  females  of  these  two  species  of  mosquitoes. 

•        HERRICK  LAB.  EX. 5 


66  STUDIES    OF   ANIMAL   TYPES 

D.  TOPICS  FOR  FURTHER  STUDY.  Write  out  a  sum- 
mary of  the  life  history  of  a  common  mosquito.  Compare 
a  mosquito  with  a  locust  in  regard  to  the  divisions  of  the 
body,  number  of  legs,  eyes,  antennae,  and  wings.  Compare 
its  mouth  parts  with  those  of  the  locust.  See  Comstock's 
"  Manual  for  the  Study  of  Insects  "  for  the  mouth  parts 
of  a  dipterous  insect.  To  what  branch  does  the  mosquito 
belong  ?  To  what  class,  order,  genus,  and  species  does  the 
common  mosquito  belong. 

For  information  on  the  mosquitoes  and  their  relation 
to  malaria  and  yellow  fever,  see  Dr.  L.  0.  Howard's  book 
on  mosquitoes. 

XX.  — THE  PERCH 

Materials.  —  A  perch,  black  bass,  or  sunfish,  live  goldfish,  dissect- 
ing pans,  scalpel,  scissors,  and  piece  of  bread. 

Directions.  —  (Although  this  exercise  pertains  especially  to  the 
perch,  the  black  bass,  sunfish,  or  any  other  common  fish  will  do  with 
very  little  modification  of  the  outline.  Small  fish,  such  as  minnows, 
may  easily  be  obtained  from  streams  and  permanent  pools  and 
placed  in  aquaria  for  observation.  In  large  towns  and  cities  it  is 
often  possible  to  have  living  goldfish  in  glass  aquaria.) 

A.  STUDY  OF  A  LIVING  FISH.  What  is  the  form  of 
the  body?  Is  the  form  of  the  fish  adapted  to  its  life  in 
the  water  ?  Is  the  tail  symmetrical  ?  That  is,  is  the  dor- 
sal lobe  of  the  same  shape  and  size  as  the  ventral  one  ? 

How  many  fins  has  the  goldfish?  Where  are  they  lo- 
cated? How  many  single  fins  are  there?  Are  any  of 
them  in  pairs?  Watch  the  fish  swim.  What  is  the  prin- 
cipal organ  of  locomotion?  Which  fin  is  used  most  in 
swimming  ?  Catch  the  fish  carefully  and  place  a  light  rub- 


THE    PERCH  67 

ber  band  about  the  anterior  (pectoral)  pair  of  fins  and 
watch  the  result.  Catch  it  once  more  and  put  the  band 
about  the  posterior  (pelvic)  pair  of  fins  and  watch  the 
result.  After  these  experiments  what  can  you  say  regard- 
ing the  functions  of  the  different  fins?  Which  fins  are 
used  to  maintain  an  equilibrium  of  the  body  ? 

Watch  the  movements  of  the  mouth  and  gill  covers.  In 
what  order  do  the  movements  follow  each  other?  What 
is  the  reason  for  these  rhythmic  orderly  movements  ? 

Watch  the  eyes.  Are  they  capable  of  movement  ?  Do 
the  eyes  move  together?  Are  the  eyes  furnished  with 
lids?  Do  they  seem  to  have  any  means  of  protection? 
Determine,  if  possible,  the  extent  of  vision. 

Place  some  food  on  the  surface  of  the  water.  Watch 
the  fish  obtain  and  swallow  this  food.  Scatter  small 
pieces  of  paper  on  the  water.  Does  the  fish  swim  for 
them  ?  Upon  what  sense  does  it  seem  to  depend  to  find 
its  food  ?  Does  it  eat  the  paper  ?  Does  it  seem  to  have 
the  sense  of  taste? 

B.  EXTERNAL  FEATURES  OF  A  FISH  (perch).  Note  the 
shape  of  the  body  from  a  dorsal  and  side  view.  What  can 
be  said  of  its  adaptation  to  swimming  through  the  water  ? 
The  body  is  flattened  from  side  to  side  or  compressed. 
Like  the  earthworm,  the  perch  is  bilaterally  symmetrical. 

Note  the  number,  situation,  size,  and  shape  of  the  fins. 
How  many  are  in  pairs?  Where  are  the  pairs  borne? 
How  many  are  borne  singly?  Are  these  in  the  middle 
line  of  the  body  ?  How  many  dorsal  fins  are  there  ?  The 
front  pair  of  fins  is  known  as  the  pectoral  fins  and  they  cor- 
respond to  the  front  pair  of  limbs  in  the  higher  animals. 
The  more  posterior  pair  are  the  pelvic  fins.  The  single  fin 
just  back  of  the  anal  opening  is  the  anal  fin. 


68  STUDIES    OF   ANIMAL   TYPES 

Study  carefully  the  two  dorsal  fins.  The  spines  of  one  are 
sharp,  stiff,  and  un jointed,  while  the  spines  of  the  other  are 
branched  at  the  ends  and  are  jointed,  therefore  flexible. 
Determine  which  fin  has  the  stiff  rays  and  which  the  soft 
ones.  The  membrane  connecting  the  rays  is  really  double, 
for  it  is  simply  a  fold  of  the  skin. 

Observe  the  tail  fin.  Is  it  symmetrical?  It  is  known 
as  a  homocercal  fin  because  its  lobes  are  equal  and  the 
backbone  does  not  extend  into  it  but  stops  at  its  base. 

Note  the  shape  and  position  of  the  eyes.  Note  the  ab- 
sence of  eyelids  and  the  transparent  membrane,  cornea, 
covering  the  eyes  for  protection.  Note  the  dark  central 
pupil  and  the  colored  circle  surrounding  it,  the  iris. 

Note  the  nostrils  in  front  of  each  eye.  The  posterior 
nostril  is  different  in  shape  from  the  anterior  one.  Deter- 
mine, by  probing  them  with  a  bristle,  if  they  open  into  the 
mouth. 

Note  that  the  body  is  covered  with  a  thin,  slimy  skin, 
the  epidermis.  Underneath  this  are  the  scales.  Note  their 
arrangement.  Find  a  place  on  the  body  where  there  are 
no  scales.  Remove  a  scale,  being  sure  to  observe  which  is 
the  free  and  which  the  attached  ends.  Place  it  under 
the  low-power  objective  and  make  a  drawing  of  it  to  show 
its  shape  and  the  difference  between  the  free  and  attached 
ends.  A  scale  with  the  posterior  edge  toothed  is  a  ctenoid 
scale.  Are  the  scales  of  the  perch  ctenoid? 

Note  the  line  running  from  tail  to  gill  cover  along  the  side 
of  the  perch.  This  is  the  lateral  line.  Examine  some  of  the 
scales  in  this  line  and  determine  how  the  line  is  produced. 

The  large  flap  on  the  side  of  the  head  is  the  operculum, 
or  gill  cover.  The  opening  beneath  the  gill  cover  is  the 
gill  opening.  The  operculum  is  composed  of  several  pieces 


THE    PERCH  69 

called  operdes.  How  many  are  there?  Along  the  lower 
and  posterior  edge  of  the  operculum  is  a  membrane  sup- 
ported by  seven  parallel  rays.  This  is  the  branchiostegal 
membrane  and  rays. 

Make  a  drawing  of  a  side  view  of  the  perch,  showing  all 
the  foregoing  points  possible. 

Raise  one  of  the  gill  covers  and  note  the  position  of  the 
gills.  How  many  are  there?  Open  the  mouth  widely  and 
depress  the  tongue  to  determine  the  connection  between  the 
gill  cavity  and  the  mouth.  Remove  most  of  the  gill  cover. 
Note  that  each  gill  consists  of  a  bony  arch  with  comblike 
filaments  on  the  posterior  edge  and  teethlike  organs,  the 
gill  rakers,  on  the  anterior  edge.  The  slits  between  the 
gills  are  the  gill  clefts.  How  many  gill  clefts  are  there? 

Draw  a  complete  gill,  showing  arch,  filaments,  and  rakers. 

Again  open  the  mouth  wide  and  note  its  size.  Note  the 
flat,  short  tongue.  Find  the  teeth  on  the  upper  and  lower 
jaws.  What  shape  and  size  are  they  ?  Which  way  do  they 
point  ?  What  purpose  would  they  seem  to  serve,  judging 
from  their  size  and  the  way  they  point? 

C.  INTERNAL  ORGANS.  Make  a  shallow  incision  from 
just  in  front  of  the  anal  opening  along  the  ventral  wall  of 
the  abdomen  through  the  tip  of  the  lower  jaw,  being  care- 
ful not  to  cut  into  the  internal  organs.  Now  make  a  deep 
cut  with  the  scalpel  along  the  lateral  line  on  the  left  side 
from  behind  forwards  and  then  remove  one  whole  side  of  the 
abdomen  being  very  careful  not  to  injure  the  air  bladder. 

Note  the  spinal  column  along  the  dorsal  side  of  the  ab- 
dominal cavity.  The  liver,  intestines,  and  other  organs  lie 
in  the  lower  part  of  the  abdominal  cavity,  while  the  thin 
air  bladder  lies  in  the  upper  part  and  its  ventral  wall 
forms  a  wall  across  the  body  cavity. 


70  STUDIES    OF   ANIMAL   TYPES 

Note  the  shining  membrane  lining  the  abdominal  cavity. 
This  is  the  peritoneum.  Note  that  there  is  another  cavity 
between  the  gill  covers  which  is  separated  from  the 
abdominal  cavity  by  a  thin  transverse  partition^  the  false 
diaphragm.  This  anterior  cavity  is  the  pericardial  cavity, 
and  contains  the  heart. 

The  air  bladder  is  the  largest  organ  in  the  abdominal 
cavity.  How  much  space  does  it  occupy?  Find  the 
pinkish  or  brownish  liver  in  the  anterior  part  of  the  abdo- 
minal cavity.  Tear  it  free  and  turn  anteriorly.  A  rather 
large  sac,  the  stomach,  will  then  be  seen.  Pass  a  probe 
down  the  gullet  into  the  stomach.  Note  that  the  stomach 
ends  blindly  at  its  posterior  end  and  that  the  intestine 
branches  off  near  the  anterior  end.  Note  several  long, 
cylindrical  appendages,  the  pyloric  cceca,  arising  from  the 
intestine  a  little  ways  from  its  origin  at  the  stomach. 
Trace  the  intestine  among  the  masses  of  fat  and  find 
that  it  is  coiled  in  its  anterior  part  and  extends  to 
the  anus. 

Find  the  greenish  bile  sac  on  the  posterior  surface  of  the 
liver. 

The  spermaries  of  the  male  are  white  and  in  the  breeding 
season  appear  as  long  white  bodies  running  toward  the 
anterior  part  of  the  abdominal  cavity,  just  under  the  air 
bladder.  The  ovary  is  an  elongated  sac  lying  in  a  corre- 
sponding position  in  the  female. 

A  small  pink  or  green  sac,  the  urinary  bladder,  lies  just 
posterior  to  the  oviduct. 

If  a  fresh  fish  is  being  dissected,  examine  the  air  bladder. 
Note  its  thin  walls.  Puncture  it.  What  is  the  result? 
Determine  if  there  are  any  blood  vessels  in  the  walls  of  the 
air  bladder. 


THE    FROG  71 

Remove  the  air  bladder  and  observe  the  dark  red  kid- 
neys extending  closely  along  the  dorsal  side  of  the  ab- 
dominal cavity,  one  on  each  side  of  the  backbone.  Just 
above  the  gullet,  in  the  pericardial  cavity,  the  kidneys 
unite  and  form  a  median,  large,  and  dark  colored  mass, 
the  head  kidney.  Find  this  mass. 

Find  the  heart  again  and  examine  it.  Of  how  many 
parts  does  it  seem  to  consist?  The  large  vessel  lying 
across  the  posterior  end  of  the  pericardial  cavity  is  the  sinus 
venosus.  The  irregular,  darker  portion  lying  below  and 
slightly  in  front  of  the  sinus  venosus  is  the  auricle.  The 
rounded,  bulblike  ventricle  lies  below  and  at  the  side  of  the 
auricle.  The  ventricle  sends  the  blood  forward  into 
the  arterial  bulb  which  lies  just  in  front  of  the  former. 
From  the  latter,  the  aorta  carries  the  blood  directly  to  the 
gills. 

D.  TOPICS  FOR  FURTHER  STUDY.  If  a  young  shark  is 
at  hand,  compare  it  with  the  perch  as  to  scales,  gill  slits, 
operculum,  situation  of  the  mouth,  etc.  Study  the  fish- 
eries of  the  United  States  from  reports  of  the  Bureau  of 
Fisheries.  Study  the  food  of  the  fresh-water  fishes. 

XXI.— THE   FROG 

Materials.  —  Living  and  preserved  specimens  of  frogs,  tub  or 
aquaria,  wire  netting,  flies,  thin  board  or  shingle,  towel,  tape, 
tacks,  thread,  corn-pound  microscope,  cover  glasses,  bristles,  dis- 
secting instruments,  dissecting  pan,  pins ;  live  frog's  eggs,  shallow 
pans,  pond  scum,  mud,  rocks,  etc. 

Directions.  —  (The  common  leopard  frog,  the  green  frog,  or  the 
bullfrog  will  serve  equally  well  for  the  following  outline.  If  desired, 
the  specimens  may  be  preserved  in  a  five  per  cent  solution  of  formalin 
while  the  dissection  is  going  on.) 


72  STUDIES    OF   ANIMAL   TYPES 

A.  STUDY  OF  A  LIVING  FROG.    Put  a  live  frog  in  a  large 
tub  or  in  an  aquarium  and  watch  it  swim.    What  legs  are 
used  in  swimming?    Watch  the  movements  of  these  legs. 
Do  the  front  legs  perform  any  active  function  in  swimming  ? 
What  position  does  the  frog  assume  when  it  is  quietly  rest- 
ing ?    Where  does  it  rest  ?     How  long  can  it  stay  below 
the  surface  ?    How  are  the  hind  legs  held  when  it  is  quiet  ? 
Why  is  the  head  held  out  of  the  water  ?    Find  the  nostrils 
near  the  tip  of  the  nose,  one  on  each  side.     Notice  the  sort 
of  rhythmic  movements  of  the  openings  to  the  nostrils. 

Put  some  wire  netting  over  the  tub  and  imprison  living 
house  flies  beneath  it.  Determine,  if  possible,  how  the 
frog  eats. 

Put  the  frog  on  the  floor  for  a  little  time  and  observe  its 
method  of  locomotion  under  these  conditions. 

Determine  how  this  animal  breathes.  Observe  the 
nostrils,  mouth,  and  abdomen,  and  describe  the  movements 
of  each. 

Make  a  drawing  of  a  living  frog  in  its  sitting  posture. 

B.  EXTERNAL  FEATURES.     Note  the  short,  wide,  hump- 
backed body  with  the  triangular  head.     Note  the  absence 
of  fins,  neck,  and  tail.     How  do  these  features  compare  with 
a  fish? 

How  do  the  hind  legs  of  the  frog  compare  with  the  front 
ones  ?  How  many  toes  on  the  hind  and  on  the  front  feet  ? 
What  is  found  between  the  hind  toes  ?  Note  that  each  leg 
has  three  parts.  The  front  leg  is  divided  into  arm,  fore- 
arm, and  hand;  the  hind  leg  into  thigh,  shank,  and  foot. 

Make  a  drawing  of  a  front  and  hind  leg  showing  the  parts. 

Note  the  smooth,  moist,  scaleless  skin  and  the  markings 
on  the  body  and  legs.  What  color  is  the  frog  above? 
What  color  is  it  below?  The  color  above  usually  accords 


THE    FROG  73 

with  the  surroundings  of  this  animal  and  makes  it  less 
conspicuous  to  its  enemies. 

How  many  eyes  has  the  frog,  and  where  are  they  situated  ? 
Note  how  they  protrude.  Touch  one  of  them  with  a  pen- 
cil. Is  the  eye  withdrawn  ?  Note  that  it  drops  downward 
and  inward.  Determine  the  number  of  lids.  Which  is 
the  thinner  and  capable  of  more  movement?  The  under 
one  is  sometimes  called  the  nictitating  membrane. 

Just  behind  each  eye  find  the  tympanic  membranes  of 
the  ears.  Note  the  white  spot  in  the  center  of  each.  This 
is  the  place  of  attachment  of  the  columella  (see  text, 
page  230). 

Note  the  wide,  capacious  mouth  and  the  fleshy  lips  bor- 
dering the  jaws. 

Circulation  of  the  blood  in  the  web  of  the  hind  foot.  —  Procure 
a  thin  board  or  shingle  five  or  six  inches  long  and  near  the 
middle  of  one  end  cut  a  V-shaped  opening  about  the  size 
of  the  expanded  web.  Wrap  the  frog  in  a  wet  towel  or 
cloth  with  a  hind  foot  protruding,  and,  with  tape,  tie  the 
animal  firmly  but  not  too  tightly  to  the  board.  Do  not 
tear  the  web,  but  stretch  it  carefully  over  the  opening  by 
attaching  threads  to  the  outside  toes  and  tying  them  to 
tacks  stuck  in  the  board.  Then  place  the  whole  firmly 
on  the  stage  of  a  microscope  and  examine  the  web  with 
the  low-power  objective. 

Note  the  network  of  blood  vessels  in  the  web.  The 
larger  vessels  running  mainly  toward  the  free  ends  of  the 
web,  and  constantly  diminishing  in  size  by  subdivision,  are 
the  arteries.  They  gradually  break  up  into  capillaries. 
The  capillaries  unite  and  form  large  vessels,  the  veins. 

Now  place  a  cover  glass  on  the  web  and  run  water  be- 
neath it,  Examine  the  web  with  the  high-power  objective. 


74  STUDIES    OF   ANIMAL   TYPES 

Determine  the  direction  of  the  blood  flow  by  the  move- 
ments of  the  bodies  (the  corpuscles)  floating  in  the 
blood.  '  t] 

There  are  two  kinds  of  corpuscles  in  the  blood,  the  red 
ones  and  the  white,  or  colorless  ones.  What  is  the  shape 
of  a  red  corpuscle?  The  red  ones,  for  the  most  part,  are 
in  the  middle  of  the  currents  while  the  white  ones  are  along 
the  edges  of  the  streams.  Note  that  the  red  ones  change 
shape  sometimes  when  crowded  or  pressed.  Do  they 
resume  their  original  shapes? 

Make  drawings  of  the  two  kinds  of  corpuscles. 

C.  INTERNAL  FEATURES.  Examine  the  mouth  and  note 
the  number  and  arrangement  of  the  teeth  on  the  upper 
jaw  and  the  absence  of  teeth  from  the  lower  jaw.  Look 
on  the  roof  of  the  mouth  for  a  patch  of  teeth. 

Note  the  long  fleshy  tongue.  Draw  it  forward  and  de- 
termine how  it  is  attached  to  the  mouth.  Note  the  sticky 
saliva  on  the  tongue.  Probably  the  manner  in  which  this 
animal  procures  food  has  already  been  determined.  If 
not,  try  again,  or  get  a  toad  and  confine  it  in  a  box  con- 
taining some  moist  earth  and  feed  it  with  flies,  beetles,  etc. 
The  toad  obtains  its  food  in  a  manner  similar  to  that  of  the 
frog,  is  much  more  at  home  in  captivity,  and  can  more 
easily  be  observed. 

In  the  back  part  of  the  floor  of  the  mouth  note  the  glot- 
tis, the  slitlike  opening  to  the  windpipe. 

Push  a  bristle  down  the  nostrils,  to  determine  where  they 
enter  the  mouth. 

Make  an  opening  in  the  tympanic  membrane  and  push  a 
bristle  through  the  cavity  of  the  internal  ear  into  the  mouth. 
The  tube  through  which  the  bristle  enters  the  mouth  is  the 
Eustachian  tube. 


THE   FROG  75 

Dissect  the  frog  under  water  in  the  pan.  Lay  the  body 
on  its  back,  stretch  out  the  legs  and  pin  them  down.  Then 
cut  through  the  skin  on  the  median  line  of  the  ventral  sur- 
face from  the  lower  jaw  to  the  posterior  end  of  the  body. 
Make  a  transverse  cut  across  the  middle  and  turn  back  the 
four  flaps  and  pin  them  down.  If  the  skin  has  been  care- 
fully cut,  the  thin  abdominal  wall  will  now  appear  unharmed. 
Note  a  dark  vein  along  the  median  line  showing  through  the 
wall.  Cut  through  the  wall  to  one  side  of  the  vein  so  as  not 
to  injure  it,  and  continue  the  slit  to  the  breastbone.  Raise 
the  breastbone  and  see  the  heart.  Then  cut  through  this 
bone  a  little  to  one  side,  and  pin  the  flaps  of  the  abdominal 
wall  out  of  the  way  to  expose  the  internal  organs. 

The  most  conspicuous  organ  is  the  reddish  liver.  How 
many  lobes  has  it  ?  Find  the  gall  bladder,  a  dark,  spherical 
sac,  on  the  under  side  of  the  liver.  Trace  its  connection 
with  the  intestine. 

Circulatory  organs.  —  Just  in  front  of  the  liver  is  the  heart, 
inclosed  in  a  thin,  transparent  sac,  the  pericardium.  Pinch 
up  the  loose  pericardium  and  cut  through  it,  being  careful 
not  to  sever  any  of  the  blood  vessels,  and  remove  as  much 
of  it  as  possible.  Note  the  heart  inside,  with  two  auricles 
at  the  base  and  the  single  ventricle  at  the  posterior  end. 
If  the  heart  is  still  beating,  it  may  be  possible  to  time  its 
pulsations. 

Note  the  large  artery  that  springs  from  the  anterior  end 
of  the  ventricle.  It  soon  divides  into  two  main  arteries, 
each  of  which  then  divides  into  three  others,  called  the  aortic 
arches.  The  anterior  arch  carries  blood  to  the  head;  the 
middle  arch  carries  blood  to  various  parts  of  the  body; 
while  the  posterior  arch  conveys  blood  to  the  lungs  and 
skin  for  aeration. 


76  STUDIES    OF   ANIMAL   TYPES 

Make  a  diagrammatic  drawing  of  the  heart  and  its 
arteries. 

Digestive  organs. —  Push  a  long  probe  through  the  pharynx 
and  gullet  into  the  stomach.  What  is  the  shape  of  the  stom- 
ach? How  large  is  it? 

The  intestine  begins  at  the  posterior  end  of  the  stomach. 
Trace  its  turns  and  windings  to  the  enlarged  posterior  por- 
tion, the  cloaca.  How  is  the  intestine  held  in  place  ?  From 
what  is  it  suspended  ?  The  thin  tissue  supporting  the  in- 
testine is  called  the  mesentery. 

The  liver  has  been  already  described. 

The  pancreas  is  a  whitish,  compact  organ  lying  between 
the  stomach  and  intestine. 

Make  a  diagram  of  the  alimentary  canal. 

Respiratory  organs.  —  Find  the  glottis  and  inflate  the 
lungs.  They  are  usually  concealed  by  the  liver.  How 
many  lobes  to  the  lungs  ?  What  color  are  they  ?  Dissect 
out  the  windpipe  and  trace  it  to  the  mouth. 

Excretory  organs.  —  There  are  two  reddish  brown  kidneys 
on  the  dorsal  side  of  the  body  cavity  near  the  cloaca.  In 
the  extreme  posterior  end  of  the  body  cavity  will  be  found 
the  urinary  bladder.  It  is  a  thin  sac  and  is  usually  empty. 

D.  DEVELOPMENT  AND  LIFE  HISTORY.  The  eggs  of  the 
frog  are  laid  in  large,  irregular,  jelly  like  masses  in  spring, 
in  the  shallower  parts  of  ponds  and  streams  near  the  shore. 
They  may  be  gathered  and  brought  to  the  laboratory  in 
water.  Place  some  of  them  in  a  large  tin  milk  pan.  Tilt 
the  pan  by  placing  something  under  one  edge,  and  put  in 
enough  water  to  cover  the  bottom  an  inch  deep  in  the  shal- 
lower part.  It  would  be  well  to  siphon  this  water  out 
occasionally  and  put  in  some  fresh.  Gather  some  mud, 
pond  scum,  rocks,  and  leaves  with  fine  slimy  sediment  on 


THE   LIZARD  77 

them  from  the  pond  and  put  them  in  the  pan.  This  material 
will  furnish  food  for  the  young  tadpoles.  New  food  should 
be  added  from  time  to  time.  Do  not  attempt  to  rear  too 
many  in  one  pan,  and  do  not  set  the  pan  in  strong  sunlight. 
Arrange  other  pans  and  experiment  with  them  by  setting 
them  in  light  of  varying  intensity  and  in  temperatures  of 
different  degrees. 

Note  the  shape  and  color  of  the  eggs.  Note  when  the 
eggs  hatch.  Note  the  appearance  of  the  very  young  tad- 
poles. Do  they  possess  feet?  How  do  they  swim?  Do 
they  ever  fasten  themselves  to  objects  in  the  water  ?  What 
color  are  they?  Observe  them  from  day  to  day  and  note 
all  the  changes  that  take  place  in  them  as  they  grow. 
How  do  the  young  tadpoles  breathe?  Find  the  gills. 
Where  are  they?  Determine,  if  possible,  when  the  gills 
disappear.  Note  that  the  young  tadpole,  as  it  grows  older, 
begins  to  come  to  the  surface  now  and  then  to  get  air. 
The  tadpole  is  now  beginning  to  use  its  lungs.  Note  the 
first  appearance  of  the  legs.  Which  pair  appears  first? 
Observe  the  tail  from  day  to  day.  Note  that  it  grows 
smaller  and  smaller.  It  is  actually  absorbed  into  the  body. 
Note  when  the  second  pair  of  legs  appear.  Note  the  time 
that  it  takes  a  young  tadpole  to  become  mature. 

It  would  be  well  to  make  careful  notes  and  even  drawings 
from  time  to  time. 

In  the  same  manner  the  life  history  of  the  toad  may  be 
easily  followed. 

XXII. —  THE  LIZARD 

Materials.  —  Specimens  of  lizards,  wooden  box,  earth,  leaves, 
wire  netting,  dissecting  instruments,  board,  tacks,  inflating  appara- 
tus (see  Appendix). 


78  STUDIES   OF   ANIMAL   TYPES 

Directions.  —  (Although  the  six-lined  lizard  was  used  in  making 
the  following  outline,  any  one  of  three  or  four  species  will  serve 
quite  as  well.) 

A.  HAUNTS  AND  HABITS  OF  LIZARDS.    Lizards  are  com- 
mon in  the  woods,  around  old  logs,  along  rail  fences,  and 
about  old  stumps  and  brush  piles.     Some  of  them  are  swift 
of  movement,  and  quickly  scurry  out  of  sight.     Others 
climb   trees  and  remain  hidden  among  the  leaves  and 
branches.     Some  can  change  color  to  suit  the  environment, 
and  some  of  them  resemble  the  bark  of  trees  upon  which 
they  live. 

B.  STUDY  OF  A  LIVING  LIZARD.    Put  a  lizard  in  a  box 
containing  some  moist  earth,  leaves,  and  a  piece  of  wood 
beneath  which  it  may  hide.     Cover  with   wire  netting. 
If  it  is  desired,  the  wire  netting  may  be  removed  when  the 
animal  is  under  observation. 

Study  its  mode  of  locomotion  and  rate  of  movement. 
See  if  it  can  climb  a  sharply  inclined,  smooth  surface. 
Try  it  on  a  rough  surface  like  the  trunk  of  a  tree  or  piece  of 
branch  with  rough  bark.  Test  its  sight.  Is  its  vision 
keen?  Offer  it  some  living  flies,  beetles,  bugs,  etc.  How 
does  it  catch  and  eat  them?  Does  it  eat  many?  What 
can  be  said  of  its  economic  value  in  destroying  injurious 
insects  ? 

Offer  it  water  and  try  and  determine  whether  it  drinks  or 
not.  If  it  does  drink,  determine  the  manner  in  which  this 
is  done. 

Determine  the  number  of  eyelids.  Thrust  a  pencil 
toward  the  eye  and  observe  the  movements  of  the  nicti- 
tating membrane  which  can  be  drawn  over  the  whole  eye. 
This  membrane  comes  out  from  the  inner  corner  of  the  eye, 
where  it  lies  folded  when  not  in  use. 


THE    LIZARD  79 

Watch  the  animal  breathe.  How  frequent  are  the  res- 
pirations ?  Describe  the  breathing  movements. 

C.  EXTERNAL  FEATURES.  Note  the  four  divisions  of 
the  body,  —  head,  neck,  trunk,  and  tail.  How  does  this 
body  division  differ  from  the  frog's  ? 

Note  the  number  of  legs  and  compare  them  with  those 
of  the  frog.  How  do  the  hind  legs  of  the  lizard  compare 
in  size  with  the  front  ones  ? 

The  fore  legs  arise  behind  the  neck,  and  each  one  consists 
of  the  upper  arm,  the  forearm,  and  hand,  which  has  five 
fingers.  Make  out  these  parts. 

The  hind  legs  also  consist  of  three  parts,  —  thigh,  shank, 
and  foot.  How  many  claws  on  each  foot?  Is  there  any 
difference  in  the  length  of  these  claws?  Note  the  situa- 
tion of  the  "  big- toe  "  claw.  The  hind  legs  arise  from  the 
trunk  more  ventrally  than  the  front  ones. 

Make  a  drawing  of  a  hind  leg  showing  all  the  parts. 

What  is  the  color  of  the  body  above  and  below  ?  How 
many  lines  are  on  the  body  ?  Where  are  they  situated  ? 

Note  that  the  body  is  covered  with  scales.  How  does 
this  feature  compare  with  the  frog  ?  Study  the  shape  and 
arrangement  of  the  scales  on  the  head,  back,  tail,  and  belly. 
How  many  longitudinal  rows  of  scales  on  the  ventral  sur- 
face? On  some  species  the  scales  are  not  in  longitudinal 
rows  on  this  surface. 

Note  that  the  mouth  is  wide  but  that  the  jaws  are  not 
dilatable  like  those  of  the  snake.  Find  the  nostrils  on  the 
sides  of  the  end  of  the  head.  They  open  into  the  mouth. 

Back  of  the  corners  of  the  mouth  note  the  tympanums 
of  the  ears.  They  are  plainly  visible. 

The  upper  and  lower  jaws  are  each  furnished  with  a  row 
of  small,  conical  teeth. 


80  STUDIES    OF   ANIMAL   TYPES 

Note  the  tongue.  Is  it  attached  like  the  tongue  of  a 
frog  ?  Observe  the  forked  extremity  of  the  tongue. 

D.  INTERNAL  FEATURES.  Lay  the  lizard  on  its  back 
on  a  pine  board  and  stretch  the  legs  to  the  right  and 
left  and  tack  them  to  the  board.  Also  put  a  tack  through 
the  tail  and  through  the  upper  jaw,  leaving  the  lower 
jaw  free. 

Seize  the  lower  jaw  and  pull  it  upward  to  show  the  size 
of  the  mouth  opening.  Find  the  teeth  on  the  jaws  and 
determine  the  shape  and  size.  Note  the  size,  shape,  and 
attachment  of  the  tongue  again. 

At  the  root  of  the  tongue  find  a  small  opening,  the  glot- 
tis. This  is  the  entrance  to  the  windpipe  that  leads  to  the 
lungs. 

Begin  immediately  back  of  the  fore  legs  and  cut  through 
the  floor  of  the  abdomen  in  a  median  line  to  the  anal  aper- 
ture. Be  careful  not  to  injure  any  of  the  internal  organs. 
Now  make  a  transverse  cut  just  behind  the  front  legs  and 
turn  the  walls  of  the  abdomen  to  the  right  and  left  and  pin 
or  tack  down  to  the  board. 

Respiratory  apparatus.  —  Use  the  inflating  apparatus 
described  in  the  Appendix  and  insert  the  point  into  the 
glottis,  and  inflate  the  lungs.  Trace  the  windpipe  to  the 
lungs.  Note  that  it  bifurcates,  a  branch  going  to  each  of 
the  lobes  of  the  lungs.  What  is  the  shape  and  color  of 
the  lobes  ?  How  far  back  does  each  lobe  extend  ? 

Circulatory  organs.  —  Note  the  heart  on  top  of  the  wind- 
pipe and  lungs.  Of  course,  in  the  natural  position  of  the 
animal,  the  heart  would  be  ventrad  of  these  organs.  The 
heart  is  inclosed  in  a  thin  sac,  the  pericardium.  Pinch  up 
a  fold  of  this  sac,  cut  through  it,  and  remove  the  heart, 
being  careful  not  to  sever  any  of  the  blood  vessels,  Note 


THE    LIZARD  81 

that  the  heart  consists  of  two  auricles  with  a  muscular 
ventricle  between  and  behind  them. 

From  the  anterior  end  of  the  ventricle  arise  three  ar- 
teries rather  closely  bound  together.  One,  the  pulmonary 
artery,  goes  to  the  lungs.  The  other  two,  right  and  left 
aortic  arteries,  send  branches  to  the  head,  trunk,  tail,  and 
other  parts  of  the  body. 

Find  several  veins,  darker  in  color  than  the  arteries,  that 
lead  to  the  heart. 

The  digestive  organs.  —  Clear  away  any  masses  of  fat  that 
may  be  in  the  posterior  part  of  the  body.  Begin  at  the 
mouth  and  trace  the  alimentary  canal,  noting  the  following 
parts :  - 

A  gullet  leading  to  the  stomach. 

The  stomach  quite  a  little  wider  than  the  gullet  and  with 
hard,  muscular  walls. 

Following  the  stomach,  the  small  intestine,  or  duodenum, 
which  is  more  or  less  coiled. 

The  duodenum  is  succeeded  by  the  large  intestine,  or 
rectum,  which  often  contains  undigested  matter. 

At  the  point  of  union  between  the  small  and  large  intes- 
tine, the  latter  is  produced  into  a  short,  blind  sac,  the  ccecum. 

The  rectum  joins  the  cloaca,  the  dilated  posterior  end  of 
the  alimentary  canal. 

The  liver  is  large  and  divided  into  a  right  and  left  lobe. 
It  lies  in  the  anterior  part  of  the  body  cavity,  and  has  a 
gall  bladder  which  connects  through  a  duct  with  the  duo- 
denum. 

The  pancreas  is  situated  in  the  loop  between  the  stom- 
ach and  small  intestine. 

Make  a  diagram  of  the  digestive  organs. 

Excretory  organs.  —  Note  the  two  dark  red  kidneys  lying 

HERRICK  LAB.  EX. 6 


82  STUDIES    OF    ANIMAL   TYPES 

in  the  posterior  part  of  the  body  cavity,  and  in  close  con- 
tact with  the  dorsal  wall.  Each  one  opens  into  the  cloaca 
through  a  delicate  duct,  the  ureter.  A  urinary  bladder 
opens  into  the  cloaca  on  its  ventral  side. 

Reproductive  organs.  —  Find  the  two  ovaries  of  the  female 
that  lie  anterior  to  the  kidneys.  They  are  irregular,  oval 
bodies,  with  their  surfaces  raised  up  into  rounded  eleva- 
tion, showing  the  position  of  the  ova.  The  oviducts  are 
wide  tubes  that  open  into  the  body  cavity  at  their  anterior 
ends,  while  their  posterior  ends  open  into  the  cloaca  just 
in  front  of  the  ureters. 

The  two  spermaries  of  the  male  are  white  oval  bodies 
in  about  the  same  position  as  the  ovaries.  The  sperm 
ducts  open  into  the  ureters. 

XXIII. — THE  ENGLISH  SPARROW 

Materials.  —  Specimens  of  English  sparrows,  cotton,  chloroform, 
pine  board,  tacks,  dissecting  instruments,  pins,  apparatus  for  in- 
flating (see  Ex.  XXI). 

Directions.  —  (Since  these  birds  have  become  a  pest,  no  com- 
punction will  be  felt  in  killing  what  are  needed  for  this  work.  It 
will  be  best  to  catch  them  alive.) 

A.  EXTERNAL  FEATURES.  Note  the  shape  of  its  body. 
Is  the  body  divided  into  the  same  parts  as  that  of  a  frog 
or  lizard?  How  many  legs  has  the  sparrow?  How  do 
they  differ  from  those  of  the  frog  ?  How  does  the  anterior 
pair  of  appendages  differ  from  the  fore  legs  of  a  frog  ?  It 
must  be  remembered  that  these  are  homologous  organs. 
What  is  the  body  covered  with  ?  Are  the  feathers  of  uni- 
form thickness  all  over  the  body  ? 

Note  the  shape  of  the  wing.    Note  that  they  are  attached 


THE    ENGLISH    SPARROW  83 

to  the  dorsal  side  of  the  body  so  that  in  flight  the  body 
hangs  suspended.  Find  three  principal  joints  in  the  wing. 
Note  the  long  quill  feathers  in  each  wing  and  in  the  tail. 
Allow  a  bird  to  fly  about  the  room  and  observe  the  move- 
ments of  the  wings.  Also  note  that  the  tail  is  used  as  a 
rudder  in  guiding  the  bird,  and  as  an  aid  in  alighting. 

Note  that  the  head  is  prolonged  into  a  horny  beak,  com- 
posed of  the  upper  and  lower  mandibles.  At  the  base  of 
the  upper  mandible  are  the  nostrils.  Note  where  they  open 
into  the  mouth.  Note  the  bristles  hanging  at  the  corners 
of  the  mouth.  These  are  the  rectal  bristles. 

Note  the  large  eyes.  How  many  eyelids  have  they? 
Note  the  membrane  that  can  be  drawn  wholly  over  the  eye. 
This  is  the  nictitating  membrane. 

(Some  of  the  above  features  can  be  best  observed  on  a  dead  bird. 
When  necessary  kill  the  bird  by  holding  a  piece  of  cotton  saturated 
with  chloroform  to  its  nostrils.) 

Below  and  behind  the  eye,  look  for  the  ears.  They  are 
hidden  by  the  feathers.  There  are  no  external  ears,  but 
the  auditory  openings  may  be  found.  The  feathers  over 
the  openings  are  not  so  compact  as  elsewhere.  Why  ? 

Feathers.  —  Examine  a  feather  in  detail.  Note  the  shaft 
running  through  the  center.  The  lower,  transparent,  hol- 
low part  is  the  quill.  It  extends  only  to  the  wide,  expanded 
portion,  the  vane.  The  remaining  part  of  the  shaft,  in  the 
middle  of  the  vane,  is  the  rachis.  Note  that  the  rachis 
is  opaque  and  solid.  In  the  lower  end  of  the  quill,  note  an 
opening.  A  small  conical  projection  of  the  skin  fits  into 
this  opening,  when  the  feather  is  attached  to  the  body. 
Observe  the  vane  closely.  It  is  made  up  of  narrow,  linear 
plates,  running  out  to  the  right  and  left  from  the  rachis. 
These  are  the  barbs.  The  barbs  are  fringed  with  similar 


84  STUDIES    OF   ANIMAL   TYPES 

but  smaller  bodies.  These  are  the  barbules.  The  barbules 
interlock  by  means  of  very  small  hooks,  thus  forming  a  con-* 
tinuous  sheet.  The  feathers  that  overlie  the  body  and  form 
the  contour  of  the  body  are  called  the  contour  feathers. 
Pull  off  the  contour  feathers  on  a  small  space  and  note  the 
down  feathers.  There  are  also  other  hairlike  feathers  that 
may  be  exposed,  called  filoplumules.  They  are  seen  on  a 
chicken  before  it  is  singed.  Separate  the  feathers  above 
the  base  of  the  tail  and  find  the  oil  gland. 

Observe  that  the  feathers  extend  down  the  leg  over  the 
knee,  leaving  only  the  ankle  exposed.  How  many  toes  has 
a  sparrow  ?  It  is  a  perching  bird,  so  note  the  arrangement 
of  the  toes. 

B.  INTERNAL  FEATURES.  Lay  the  bird  on  its  back  on 
a  pine  board,  stretch  the  wings  and  legs  out,  and  tack  them 
to  the  board.  Part  the  feathers  and,  with  a  pair  of  scissors, 
cut  just  through  the  skin  along  the  middle  line  from  the 
tail  to  the  base  of  the  lower  mandible.  Work  the  cut  edges 
of  the  skin  loose  from  the  sides  of  the  body,  and  pin  out  of 
the  way.  Note  the  edge  of  the  breastbone,  or  sternum, 
in  the  middle  line.  Note  on  each  side  the  large  pectoral 
muscles  that  move  the  wings.  It  is  these  muscles  that 
furnish  the  white  meat,  or  breast,  of  a  turkey  or  chicken. 
Where  are  the  largest  muscles  in  a  frog  ?  Why  ? 

Cut  away  all  the  breast  muscles.  Note  the  lateral  ribs 
attached  to  the  sternum.  Note  the  wishbone  in  front  of  the 
sternum.  It  is  made  up  of  the  two  collar  bones,  clavicles, 
grown  together  at  their  inner  ends.  Note  the  coracoid 
bones  extending  from  the  anterior  end  of  the  sternum. 
Remove  the  wishbone  and  coracoid  bones,  cut  away  the 
abdominal  wall,  and.  cut  the  ribs  from  the  sternum  on  each 
side  and  remove  the  sternum  entirely.  At  the  base  of  the 


THE    ENGLISH    SPARROW  85 

tongue,  find  the  U-shaped  liyoid  bone  surrounding  the  front 
of  the  glottis. 

Respiratory  organs.  —  The  glottis  opens  into  the  larynx, 
a  slightly  swollen  chamber.  From  the  larynx,  the  trachea 
extends  posteriorly,  until  it  branches  into  two  small  tubes, 
the  bronchi.  At  the  union  of  the  bronchi  and  trachea  is  a 
swollen  portion,  the  syrinx.  It  has  cords  stretched  across 
the  inside.  This  is  the  song  box  of  the  bird.  Trace  the 
bronchi  to  the  lungs.  Inflate  the  lungs  through  the  glottis, 
and  note  the  large  air  sacs  in  the  abdomen  that  are  connected 
with  the  lungs. 

In  observing  the  lungs,  the  viscera  had  probably  to  be 
pushed  aside.  Allow  them  to  return  to  place.  Note  the 
heart,  with  the  large  blood  vessels  leading  from  'it.  Do  not 
cut  them  yet.  Dissect  out  and  remove  the  trachea  and 
anterior  ends  of  the  bronchial  tubes. 

Digestive  organs.  —  Note  the  gullet  beneath  the  trachea. 
In  the  middle  of  the  gullet  is  an  enlargement  forming  the 
crop.  Inflate  the  gullet  to  show  the  crop.  The  gullet, 
after  leaving  the  crop,  soon  enters  the  stomach,  which  is 
difficult  to  find  because  it  is  scarcely  larger  than  the  gullet 
itself.  The  stomach,  however,  ends  at  the  gizzard,  which 
is  a  thick-walled  organ  for  grinding  the  food.  Find  the 
gizzard.  The  intestine  starts  from  the  posterior  end  of  the 
gizzard  and  immediately  forms  a  loop  which  is  known  as 
the  duodenum.  Within  the  loop  forming  the  duodenum 
is  a  pinkish  gland,  the  pancreas.  Behind  the  heart  is  the 
large,  brownish  liver  that  empties  its  bile  into  the  duo- 
denum. The  intestine  is  considerably  widened  at  the  pos- 
terior end.  This  widened  portion  is  the  cloaca.  On  each 
side  of  the  intestine  near  the  end  is  a  blind  sac.  These 
are  called  the  cceca. 


86  STUDIES  OF  ANIMAL  TYPES 

Circulatory  organs.  —  Cut  the  sac  about  the  heart.  It  is 
called  the  pericardium.  What  is  the  shape  of  the  heart? 
The  heart  has  four  chambers,  like  that  of  the  mammals. 
Snip  off  the  posterior  end  of  the  heart  and  note  that  the 
ventricles  are  distinct.  The  auricles  are  situated  at  the 
anterior  end  of  the  heart.  The  sparrow,  therefore,  has  a 
double  circulation. 

Note  the  large  artery  coming  off  from  the  left  ventricle. 
This  is  the  aorta.  Note  that  it  soon  gives  off  two  branches, 
the  innominate  arteries.  Each  of  these  divide  into  three 
smaller  arteries.  The  aorta  runs  along  the  back  toward 
the  posterior  end  of  the  body.  The  right  ventricle  is  con- 
nected directly  with  the  lungs  by  the  right  and  left  pulmonary 
arteries.  The  blood  is  brought  back  to  the  left  auricle 
by  the  right  and  left  pulmonary  veins.  The  blood  system 
may  be  injected  and  studied  in  detail.  For  directions,  see 
Needham's  "  Lessons  in  Zoology"  or  Parker's  "Zootomy." 

Excretory  and  reproductive  organs.  —  Look  in  the  body 
cavity,  near  the  backbone,  in  the  posterior  part  of  the  body 
for  the  kidneys.  They  are  three-lobed,  and  have  two  tubes, 
the  ureters,  running  from  them  to  the  cloaca.  The  kidneys 
are  partly  hidden  by  the  reproductive  organs.  In  the  male, 
the  latter  consist  of  a  pair  of  roundish,  or  oval,  light-col- 
ored testes.  In  the  female,  they  consist  of  a  large  ovary, 
sometimes  containing  the  half -formed  eggs. 

Examine  the  bones  of  the  sparrow  and  see  if  they  are 
hollow. 

C.  FIELD  STUDY  OF  THE  SPARROW.  Very  interesting 
field  studies  may  be  carried  on  in  connection  with  this 
bird.  Observe  it  in  its  natural  haunts.  Is  it  social  or 
solitary  ?  What  does  it  eat  ?  Can  it  sing  ?  Can  it  hear  ? 
Can  it  see  well  ?  How  does  it  behave  toward  other  birds  ? 


THE    GRAY    RABBIT,    OR    COTTON   TAIL  87 

From  a  study  of  its  food  would  you  judge  it  to  be  helpful 
or  injurious  to  the  farmer?  Where  does  it  build  its  nest? 
Of  what  material  is  it  built?  When  is  the  nest  made? 
How  many  eggs  are  laid?  When  do  they  hatch?  Are 
the  young  birds  helpless  ?  What  do  the  young  birds  eat  ? 
Is  there  more  than  one  brood  of  young  in  a  season  ? 

D.  TOPICS  FOR  FURTHER  STUDY.  Write  out  the  chief 
characteristics  of  the  sparrow.  Write  a  summary  of  the 
changes  through  which  the  food  goes  in  its  passage  along 
the  alimentary  canal.  Write  a  summary  of  the  circulation 
of  the  blood,  tracing  its  route,  step  by  step,  beginning  at 
the  left  auricle.  Sum  up  the  processes  of  respiration,  de- 
scribing the  organs  concerned.  Name  and  describe  the  or- 
gans of  excretion,  giving  the  particular  function  of  each. 

XXIV.  —  THE  GRAY  RABBIT,   OR  COTTON  TAIL 

Materials.  —  Specimens  of  rabbits,  dissecting  board,  dissecting 
instruments,  alcohol. 

Directions.  —  (The  wood  rabbit,  gray  rabbit,  or  cotton  tail,  is 
found  North  and  South  and  East  and  West.  It  can  be  easily  trapped 
in  a  box  trap,  and  serves  well  as  a  typical  mammal.  If  desired,  a 
cat  may  be  used  instead.) 

A.  EXTERNAL  FEATURES.  Note  the  body  covered  with 
hair.  Note  the  thick,  soft  fur  next  to  the  body,  with  long 
stiff  hairs  tipped  with  black  sticking  up  through  the  fur. 
Note  the  stiff,  bristlelike  hairs  above  and  below  the  eyes, 
and  on  each  side  of  the  mouth.  Examine  the  soles  of  the 
feet.  Are  they  smooth  or  hairy?  Note  the  long  ears. 
How  are  they  held  in  life?  Note  the  eyes  wide  apart. 
Note  the  cleft  upper  lip.  Are  the  legs  all  of  the  same  length  ? 
Which  are  longer  and  why?  How  does  a  rabbit  travel? 


88  STUDIES    OF   ANIMAL   TYPES 

Note  the  tail.  Now  does  it  compare  with  that  of  a  cat? 
What  color  is  the  tail  ?  What  color  is  found  on  the  breast 
beneath  the  head  ? 

B.  INTERNAL  FEATURES.  In  dissecting  the  rabbit,  it  is 
best  to  lay  it  upon  a  flat  board  somewhat  longer  than  the 
animal.  In  examining  the  head,  it  is  best  to  remove  the 
skin  entirely.  To  do  this,  cut  through  the  skin  around  the 
neck  and  pull  it  off  over  the  head  wrong  side  out,  cutting 
carefully  where  needed. 

Head.  —  Note  the  cartilages  at  the  bases  of  the  ears,  that 
support  them,  and  also  the  muscles  that  move  the  ears. 
Cut  off  the  ears  and  note  the  auditory  canal  that  leads 
into  the  head. 

After  the  skin  is  removed  begin  at  the  corner  of  the  mouth 
and  cut  through  the  cheek  in  a  posterior  direction,  severing 
the  lower  jaw  from  the  upper  where  it  is  hinged,  and  then 
forcibly  turn  that  half,  or  ramus,  of  the  lower  jaw,  break- 
ing its  connection  in  front.  This  will  lay  open  the  mouth 
cavity. 

Observe  that  there  are  two  pairs  of  long  curved  teeth 
in  front,  the  incisors,  one  pair  on  each  jaw.  How  do  they 
come  together?  Turn  back  the  cut  half  of  the  lower  jaw 
and  observe  this  point.  Are  the  edges  sharp  or  dull  ? 
Note  the  pair  of  small  incisors  on  the  upper  jaw  just  back 
of  the  large  ones.  What  are  the  incisors  for? 

Note  farther  back,  the  molars.  How  many  pairs  above 
and  below  ?  How  do  these  meet  ?  Are  the  surfaces  smooth 
and  are  they  flat  or  chisel-edged  ?  Note  the  space  without 
teeth  between  the  incisors  and  molars.  What  teeth  occupy 
this  space  in  your  own  mouth  ? 

Note  the  tongue.  What  shape  is  it?  Where  is  it  fas- 
tened to  the  mouth?  Is  it  thick  or  thin?  Is  there  any 


THE    GRAY    RABBIT,    OR    COTTON    TAIL  89 

difference  in  the  softness  and  roughness  of  the  anterior 
and  posterior  part  of  the  tongue  ?  The  free  anterior  part 
has  taste  papillae  on  its  surface.  On  the  posterior  part  of 
the  tongue  are  four  large  papilla  arranged  transversely 
across  the  tongue  in  a  curved  line. 

The  middle  part  of  the  roof  of  the  mouth  is  termed  the 
palate.  The  anterior  portion  has  transverse  ridges,  and 
is  hard,  hence  is  called  the  hard  palate.  The  posterior 
portion  is  without  ridges  and  is  soft,  hence  is  called  the 
soft  palate.  Note  that  the  soft  palate  terminates  in  a  free 
pendulous  flap.  Just  above  the  free  end  of  the  soft  palate 
find  the  nasal  opening,  or  chamber.  Now  cut  away  the 
soft  palate  and  find  the  two  tubes,  Eustachian  tubes,  that 
lead  from  the  ears  into  the  nasal  chamber,  one  on  each  side. 

There  are  also  ducts  from  four  pairs  of  salivary  glands 
entering  the  mouth.  If  possible,  find  these  glands  and 
their  ducts. 

The  parotid  gland  lies  just  below  and  in  front  of  the  ex- 
ternal auditory  canal.  The  duct  leading  from  it  passes  an- 
teriorly, and  opens  on  the  inside  of  the  cheek  opposite  the 
second  upper  molar  tooth. 

The  two  submaxillary  glands  lie  between  the  angles  of 
the  lower  jaw.  Their  ducts  open  on  the  floor  of  the  mouth 
beneath  the  tongue,  about  half  way  between  the  base  of 
the  tongue  and  the  lower  incisors,  and  near  the  median 
line. 

The  sublingual  gland  lies  on  the  inside  of  the  mandible  a 
little  anterior  to  the  base  of  the  tongue.  It  is  small,  and  its 
duct  is  difficult  to  find,  but  opens  under  the  tongue. 

The  infraorbital  gland  lies  just  below  and  in  front  of  the 
eye.  Its  duct  passes  downward  to  the  cheek,  and  opens 
near  that  of  the  parotid  gland. 


90  STUDIES    OF   ANIMAL   TYPES 

The  mouth  is  continued  posteriorly  by  a  funnel-shaped 
chamber,  the  pharynx.  The  small  end  of  the  pharynx  leads 
directly  into  the  gullet,  or  esophagus.  In  the  floor  of  the 
pharynx,  just  before  reaching  the  gullet,  is  an  opening,  the 
glottis,  which  leads  into  the  windpipe.  The  glottis  is  guarded 
by  an  erect  flap  of  cartilage,  the  epiglottis.  The  epiglottis  is 
raised  when  the  animal  breathes,  but  is  closed  down  when 
food  is  swallowed  so  that  it  can  pass  directly  on  into  the 
gullet. 

Body.  —  The  legs  must  now  be  fastened  down.  Extend 
the  hind  ones  backward  and  the  front  ones  forward,  with 
the  rabbit  on  its  back,  and  tack  them  to  the  board.  Slit 
the  skin  from  front  to  rear,  peal  it  off,  and  turn  to  the  sides 
out  of  the  way.  Note  the  ribs  in  front,  inclosing  the  thorax; 
also  the  soft  abdomen  to  the  rear  of  the  thorax.  Cut  the 
ribs  off  along  each  side  of  the  animal,  and  remove  them 
entirely,  thus  exposing  the  cavity  of  the  thorax,  being  care- 
ful to  injure  none  of  the  contained  organs. 

Note  the  diaphragm,  a  thin  muscular  partition  dividing 
the  thorax  from  the  abdomen.  What  is  its  shape  ?  Which 
cavity  is  the  concave  side  toward,  and  which  the  convex 
side  ?  Note  the  liver  close  against  the  posterior  side  of  the 
diaphragm.  Note  the  lungs  in  the  thorax  on  the  anterior 
side  of  the  diaphragm.  What  color  are  they?  Lift  them 
in  the  hand.  Are  they  light  or  heavy  ?  Why  ?  They  are 
commonly  called  "  lights."  What  lies  between  the  lungs? 
What  is  the  shape  of  the  heart  ?  Which  way  does  its  small 
end  point?  The  heart  lies  within  a  membranous  pouch 
called  the  pericardium.  Note  that  the  cavity  of  the  thorax 
is  lined  with  a  thin,  delicate  membrane  known  as  the  pleura. 

Return  to  the  gullet  and  follow  it  to  the  stomach.  What 
shape  is  the  stomach?  How  does  it  lie?  Estimate  the 


THE    GRAY    RABBIT,    OR    COTTON    TAIL  91 

amount  it  will  hold.  What  leaves  the  stomach  at  the  end 
opposite  the  gullet?  The  first  part  of  the  intestine,  be- 
ginning at  the  stomach,  is  the  duodenum.  This  is  folded 
upon  itself  forming  a  long  narrow  loop.  The  opening  of 
the  stomach  into  the  duodenum  is  guarded  by  a  valve,  the 
pylorus,  which  prevents  food  from  leaving  the  stomach  until 
it  has  been  properly  acted  upon.  The  ducts  from  the  gall 
bladder  and  pancreas  enter  the  duodenum.  Find  the  gall 
bladder  beneath  one  of  the  lobes  of  the  liver.  The  pancreas 
is  a  whitish  mass  in  the  loop  of  the  duodenum.  Lying  be- 
hind the  stomach  is  a  large,  flat,  dark  red  gland,  the  spleen. 

Following  the  duodenum  is  the  small  intestine  which  is 
much  folded.  To  complete  the  alimentary  canal  is  the 
large  intestine.  Where  the  large  and  small  intestines  join 
is  a  large  pouch  that  takes  up  considerable  room  in  the 
abdominal  cavity.  In  fact,  it  is  the  most  conspicuous  part 
of  the  alimentary  canal.  This  is  the  ccecum.  It  ends  in  a 
fingerlike  process  known  as  the  vermiform  appendix,  which, 
in  man,  is  often  the  seat  of  the  disease  known  as  appendicitis. 

Note  the  bean-shaped  kidneys  attached  to  the  dorsal  side 
of  the  abdominal  cavity.  Note  a  long,  white  duct,  the 
ureter,  passing  downward  from  each  kidney  to  the  bladder, 
which  lies  ventral  to  the  large  intestine. 

Begin  again  at  the  glottis.  Just  below  is  the  larynx,  the 
voice  chamber.  From  this  leads  the  windpipe,  or  trachea. 
Note  the  cartilaginous  rings  about  the  trachea.  Note  that 
the  trachea  soon  divides  into  two  tubes,  the  bronchi.  Note 
that  one  passes  to  the  root  of  each  lung.  Cut  the  larynx 
open  and  find  the  vocal  cords. 

The  heart  and  circulation  are  very  similar  to  those  of  the 
sparrow,  and  the  directions  given  there  will  suffice  for  the 
rabbit. 


92  STUDIES    OF   ANIMAL   TYPES 

Skeleton  and  nervous  system.  —  Dissect  out  carefully  the 
backbone  without  breaking  its  connections  anywhere,  and 
clean  it  as  well  as  possible.  Examine  the  vertebrae  and 
count  them.  There  are  five  groups  of  vertebrae :  the  neck 
(cervical)  vertebrce;  the  chest  (thoracic)  vertebrce,  to  which 
are  attached  the  ribs;  the  back  (lumbar)  vertebrce,  which 
have  no  ribs  attached  to  them  and  are  the  largest  of  all; 
the  sacral  vertebrce,  which  are  fused  together ;  and  the  tail 
(caudal)  vertebrce.  How  many  vertebrae  in  each  region? 
Note  the  soft,  white  cord  running  through  the  vertebrae. 
This  is  the  spinal  cord.  Trace  it  to  the  head  and  determine 
its  connection  with  the  brain.  Cut  away  the  top  of  the 
skull  and  note  the  brain.  Remove  the  brain  carefully, 
cutting  all  the  nerves,  and  place  it  in  alcohol.  Note  that 
the  brain  and  spinal  cord  occupy  a  cavity  on  the  dorsal 
side  of  the  animal.  Remember  that  the  other  great  cavity 
of  the  rabbit's  body,  composed  of  the  thoracic  and  abdom- 
inal cavities,  lies  on  the  ventral  side  of  the  body. 

Make  a  diagrammatic  cross  section  of  the  body  showing 
these  cavities  and  their  contents. 

When  removing  the  brain  take  great  care  and  note  the 
twelve  pairs  of  cranial  nerves  that  branch  off  from  it.  The 
brain  is  made  up  of  the  cerebrum,  which'  consists  of  two  large 
convoluted  bodies,  the  cerebral  hemispheres;  the  olfactory 
lobes,  that  lie  in  front  of  the  cerebrum ;  the  cerebellum,  which 
lies  posterior  to  the  cerebral  hemispheres  on  the  dorsal  side, 
and  which  consists  of  a  large  central  lobe,  two  oblique  lateral 
lobes,  and  a  pair  of  small  flocular  lobes  on  the  outer  edges. 
Just  behind  the  central  lobe  of  the  cerebellum  is  the  medulla. 

Appendages.  —  Compare  the  fore  limbs  of  the  rabbit  with 
the  wings  of  a  sparrow.  Note  the  difference  in  function 
and  structure.  Clean  the  feathers  and  flesh  from  the  wing 


THE    GRAY    RABBIT,    OR  COTTON    TAIL  93 

and  the  hair  and  flesh  from  the  leg,  being  careful  «to  retain 
all  the  bones  of  each  in  their  proper  relations  to  each  other. 

Make  a  drawing  of  each  organ,  name  the  bones  in  each, 
and  compare  the  structure  of  the  two.  How  do  they 
differ  ?  How  do  they  resemble  each  other  ?  Note  that  the 
wing  of  a  bird  and  the  leg  of  a  mammal  are  surprisingly 
alike.  They  are  homologous  organs. 

If  it  is  desired  to  make  a  more  extended  study  of  the 
nervous  system  and  of  the  skeleton,  consult  Needham's 
"  Lessons  in  Zoology  "  and  Parker's  "  Zootomy." 

C.  TOPICS  FOR  FURTHER  STUDY.  Compare  a  diagram- 
matic cross  section  of  the  body  of  a  rabbit  with  that  of  an 
earthworm.  Show  the  differences  and  similarities.  Sum 
up  the  chief  characteristics  of  the  rabbit.  To  what  class 
does  it  belong  ?  Give  the  chief  characteristics  of  that  class. 
Compare  the  rabbit  with  the  sparrow,  writing  out,  in  parallel 
columns,  the  differences  and  similarities. 


APPENDIX 

IN  the  laboratory  exercises  many  directions  were  given 
for  obtaining  and  treating  the  animals  studied.  But  cer- 
tain apparatus,  reagents,  and  methods  are  demanded  in  the 
work  that  we  could  not  speak  of  there.  These  we  shall  dis- 
cuss briefly  and  simply  in  the  following  paragraphs. 

EQUIPMENT.  —  For  practical  work  in  dissection,  a  well- 
lighted  room,  furnished  with  steady,  flat-topped  tables, 
from  28  to  30  inches  high,  is  needed.  For  some  of  the  work, 
compound  microscopes  (Fig.  1,  page  6)  are  a  necessity.  Ex- 
cellent ones  can  be  bought  for  $25  or  $30  apiece.  If  one  or 
more  of  these  cannot  be  had,  some  of  the  exercises  must  be 
omitted.  Simple  microscopes  with  simple  lenses  may  be 
obtained  at  a  small  expense,  and  are  a  great  aid.  With 
the  microscopes,  should  be  provided  glass  slides,  cover 
glasses,  and  watch  crystals.  Forceps  with  corrugated  points 
and  scissors  with  straight  and  curved  points,  should  be 
accessible  to  the  student,  being  furnished  either  by  himself 
or  by  the  school  authorities.  The  student  should  also  have 
a  scalpel,  paper  of  ribbon  pins,  and  dissecting  needles 
(Fig.  2) .  The  dissecting  needles  may  be  made  by  forcing 
steel  needles,  head  first,  into  the  ends  of  neatly  rounded 
pine  sticks  of  appropriate  size  for  handling.  If  possible, 
dissecting  pans  of  good  tin  or  galvanized  iron,  about  5  by 
8  inches,  and  2  inches  deep,  with  flaring  sides,  should  be 
provided  for  use  in  certain  dissections.  Across  the  pan, 
J  inch  from  the  bottom,  solder  a  wire,  then  run  melted 

95 


APPENDIX 


paraffin  into  the  pan  until  it  stands  J  inch  deep  over  the 
bottom.  When  it  cools  the  wire  will  hold  it  in,  and  speci- 
mens may  be  pinned  to  it  at  will. 


FIG.  2.  —  Dissecting  Instruments. 

REAGENTS.  —  A  few  reagents  are  necessary  in  preserving 
the  specimens  and  for  other  purposes.  Alcohol,  95  %  and 
85  %,  and  formalin,  4  %,  are  necessary  for  preserving  speci- 
mens. 80  %  and  85  %  alcohol  may  be  made  from  the 
95  %  alcohol  by  dilution  with  water.  A  normal  salt  solution 
(a  |  %  solution  of  salt  in  water)  is  useful  in  mounting  speci- 
mens that  might  be  destroyed  by  the  osmotic  power  of 
water.  Glycerin,  for  mounting  objects  temporarily;  Canada 
balsam,  for  mounting  hard  objects ;  and  20  %  nitric  acid,  for 
preparing  tissues  to  dissect  the  nervous  system,  are  also  de- 
sirable. Methyl  green  is  useful  in  staining  fresh  or  preserved 
tissues.  Dissolve  it  in  water,  using  about  as  much  powder 
as  the  water  will  dissolve,  and  add  a  few  drops  of  acetic  acid. 


APPENDIX  97 

DISSECTIONS.  —  All  dissections  of  small  animals  should 
be  made  in  pans  under  water.  The  different  specimens 
may  be  pinned  out  on  the  paraffin  with  ribbon  pins.  If 
the  student  is  working  on  fresh  specimens,  and  is  not  able 
to  finish  them  in  one  day  and  wishes  to  keep  them  fresh, 
add  several  drops  of  carbolic  acid  to  the  water. 

INJECTIONS.  —  Blood  vascular  and  water  vascular  systems 
are  more  easily  studied,  if  injected  with  a  colored  solution. 
The  following  solution  is  a  good  one:  One  part  gelatin 
to  four  parts  of  water.  Soak  the  gelatin  thoroughly  in 
the  water,  and  add  one  part  of  a  saturated  solution  of 
acetate  of  lead  in  water,  and  one  part  of  a  saturated  solu- 
tion of  potassium  bichromate.  These  are  best  mixed  while 
hot,  because  the  gelatin  is  then  liquid.  Filter  the  whole, 
hot,  and  inject  the  specimen  while  the  mixture  is  warm. 
A  syringe  is  necessary  for  the  injection.  Attach  a  piece  of 
glass  tubing  drawn  to  a  point  to  the  end  of  the  syringe  by 
a  rubber  tube.  There  should  be  a  constriction  near  the 
point  of  the  glass  tube,  to  afford  an  opportunity  to  tie  an 
artery  or  vein  to  it.  Several  pieces  of  tubing  should  be 
made  with  different  sized  points  to  fit  various  sized  organs. 
By  removing  the  syringe,  the  remaining  part  of  the  appara- 
tus will  serve  admirably  to  inflate  the  lungs,  alimentary 
canal,  etc.,  of  the  animals  studied. 

PRESERVING  SPECIMENS.  —  Ordinary  specimens  may  be 
preserved  for  museum  use  in  85  %  alcohol.  Some  may  be 
well  preserved  in  4  %  formalin.  Certain  preparations  of 
the  different  organs  of  the  body  made  during  the  progress 
of  the  work  may  be  preserved  in  Fischer's  solution.  It  is 
made  as  follows:  50  cc.  of  formalin,  15  g.  of  zinc 
chloride,  100  g.  of  sodium  chloride  (common  salt),  and 
2000  cc.  of  water.  Mix  them  until  dissolved. 

HERRICK    LAB.    EX. 7 


98  APPENDIX 

PREPARING  SKELETONS.  —  If  the  pupils  wish  to  study 
skeletons,  they  may  be  prepared  as  follows :  Remove  all 
skin,  viscera,  and  flesh  possible;  boil  the  skeleton  for  40 
minutes  in  a  soap  solution,  one  part,  and  water  four  parts ; 
boil  again  30  minutes,  in  equal  parts  of  the  soap  solution 
and  water;  rinse  the  bones  in  cool  water,  clean  and  dry 
them.  The  soap  solution  is  made  as  follows :  mix  200  cc. 
of  water,  12  g.  saltpeter,  75  g.  hard,  white  soap,  and  heat 
until  all  is  dissolved.  Then  add  150  cc.  of  strong  am- 
monia. 

COLLECTING  AND  REARING  INSECTS.  —  Insects  are  the 
most  convenient  and  easy  to  rear  and  observe  of  all  animals. 
They  can  be  studied  with  apparatus  made  at  home  with 
very  little  cost.  If  all  the  practical  work  in  a  course  in 
zoology  should  be  done  with  insects  and  birds  very  satis- 
factory results  might  be  obtained,  although  such  a  course 
would  be  unbalanced.  In  discussing  the  subject  of  collect- 
ing and  rearing  insects,  the  author  will  quote  freely  from 
"  Insect  Life  "  by  Professor  J.  H.  Comstock. 

The  articles  necessary  in  rearing  and  studying  insects  are 
a  net,  killing  bottle,  pins,  cork,  boxes,  and  aquarium  jars. 

NET.  —  Find  a  broom  handle  and  make  a  groove,  about 
6  inches  long  and  deep  enough  to  receive  a  lead  pencil,  on 
each  side  of  it  at  the  larger  end  (Fig.  3,  a).  Then  obtain 
a  piece  of  No.  3  galvanized  wire,  3  feet  6  inches  long,  and 
bend  it  in  the  form  of  a  circle,  leaving  about  6  inches'  at 
each  end  bent  back  to  be  laid  in  the  grooves  on  each  side 
of  the  handle  (Fig.  3  6).  Wind  spool  wire  closely  and 
tightly  about  the  stick  over  the  ends  of  the  wire,  until 
securely  fastened.  Buy  J  of  a  yard  of  heavy  sheeting,  and 
fold  it  over  the  wire  ring  double.  Then,  out  of  f  of  a  yard 
of  cheese  cloth,  make  a  bag  not  quite  as  deep  as  your 


APPENDIX 


99 


arm  is  long  and  sew  it  to  the  piece  of  sheeting  on  the 
wire  ring. 

How  TO  USE  THE  NET.  —  Most  insects  are  quick  of 
movement  and  do  not  remain  still  long  at  a  time.  To 
catch  them,  one  must  give  quick,  vigorous  strokes  with  the 


FIG.  3. —  Insect  net ;  a,  groove  in  the  handle  to  receive  the  ends  of  the  wire,  6. 
Below,  the  net  is  shown  complete. 

net.  To  keep  the  insect  in  the  net  when  once  caught,  give 
the  handle  a  quick  turn  to  throw  the  lower  part  of  the  bag 
across  the  wire  ring,  thus  closing  the  mouth  of  the  net  until 
ready  to  take  out  the  insect.  To  sweep  the  grass  for  insects, 
grasp  the  handle  of  the  net  firmly  in  both  hands  and  pass  it 
quickly  from  right  to  left,  over  the  grass,  in  front  of  yourself 
while  walking.  The  same  net  may  be  used  for  dipping  up 
aquatic  insects,  although  it  must  be  thoroughly  dried  before 
using  again  for  general  purposes. 

KILLING  BOTTLE.  —  A  wide-mouthed  bottle  is  the  first 


100 


APPENDIX 


bottle. 


requisite.  A  quinine  bottle  answers  admirably  (Fig.  4). 
A  straight  vial  .without  a  shoulder  is  convenient  to  carry 
in  the  vest  pocket.  In  the  bottom  of  the  quinine  bottle, 
put  about  a  teaspoonful  of  cyanide  of  potas- 
sium (poisonous).  Usually  this  material  is 
in  lumps.  Pulverize,  pour  it  into  the  bottle, 
and  pack  it  down  evenly  with  the  flat  end 
of  a  lead  pencil.  Pour  on  top  of  it  enough 
dry  plaster  of  Paris  to  cover  it  from  J  to  f 
of  an  inch  in  depth.  Pour  just  enough 
water  —  a  few  drops  at  a  time  —  on  the 
plaster  to  make  it  set  on  top.  It  can  be 
smoothed  and  packed  with  a  lead  pencil. 

-^o  no^  we^  ^ne  plas^er  all  the  way  to  the 
cyanide,  else  the  cyanide  will  dissolve  and 
make  the  bottle  very  moist  and  sticky,  thus  ruining  the 
insects.  If  the  bottle  is  too  moist,  put  in  circles  of 
blotting  paper.  Leave  the  newly  made  bottle  open  over 
night,  so  that  it  will  dry  out.  Then  cork,  and  it  is  ready 
for  use.  If  care  is  exercised  to  keep  the  bottle  corked,  it 
will  last  a  whole  season. 

Another  method  of  making  a  killing  bottle  is  to  pour 
\  inch  of  dry  sawdust  over  the  cyanide  and  force  a  circle 
of  thick  blotting  paper  into  the  bottle  to  hold  the  sawdust 
and  cyanide  in  place.  The  circle  of  paper  should  be  slightly 
larger  than  the  inside  of  the  bottle,  that  it  may  fit  tightly. 
With  this  method  the  bottle  may  be  used  again  and  the 
cyanide  renewed  when  it  has  lost  its  strength.  Moreover, 
the  bottle  is  much  lighter  than  if  plaster  of  Paris  is  used. 
Such  a  bottle  has  a  disadvantage  from  the  liability  of  the 
blotting  paper  to  work  loose  and  allow  the  sawdust  and 
cyanide  to  mix  up  with  the  insects.  The  bottle  should  be 


APPENDIX 


101 


labeled  poison,  and  care  should  be  taken  not  to  inhale  the 

fumes  that  come  from  it,  for  they  are  deadly  poison  when 

inhaled  in  sufficient  quantity.     One  will  soon  become  expert 

in  catching   many  insects   in  the 

bottle  directly.     Many  insects  may 

be  caught   by  holding  the  bottle 

under  them,   when    they   are    on 

flowers,  for  instance,  and  knocking 

them  into  the  bottle  with  the  cork, 

stopping  the  mouth  quickly. 

PINS.  —  Common  pins  are  too 
thick  and  corrode  too  easily.  It 
is  best  to  buy  German  insect  pins ; 
they  cost  fifteen  cents  a  hundred,  or 
less  if  bought  in  larger  quantities. 
Nos.  3  and  5  will  be  most  used. 
For  small  insects,  No.  1  is  necessary. 
Pin  insects,  except  beetles,  down 
through  the  middle  of  the  thorax 
(Fig.  5).  Pin  beetles  through  the 


FIG.  5.  —  An  insect  properly 
pinned  and  labeled. 


right  wing  cover,  just  anterior  to  the  middle  of  the  body. 

Put  a  small  label,  containing  the  date  and  place  of  capture, 

____™^  on  the  pin  below  the  in- 

___..  — gg=re=^  "    7**=s»>_ 

^|j3|    sect's  body.     Many  tiny 

I  -  ^    insects  must  be  glued  to 

%a%  |f    card  points   or  impaled 

on  the   points  of   small 

FIG.  G.-  insect  box,  made  of  wood,       P^s,  the  larger  ends  of 

with  glass  top.  which,   after    the   heads 

have  been  cut  off,  are  stuck  into  small  pieces  of  cork  or 

blotting  paper,  which  in  turn  are  put  on  larger  pins. 

BOXES.  —  The  pinned  insects  should  be  kept  in  boxes  or 


102 


APPENDIX 


drawers  that  have  bottoms  lined  with  corn  pith  or  sheet 
cork  to  receive,  the  pins.     Cigar  boxes  are  good,  but  all 

boxes  of  that  kind  are  loose  and 
permit  small  insects  to  enter  that 
live  upon  and  destroy  the  pinned 
specimens.  Tight  boxes  with  glass 
covers  made  especially  for  the  pur- 
pose are  best  for  all  permanent 
collections  (Fig.  6).  See  "  Insect 
Life,"  pp.  306-309,  for  directions 
for  making  these  boxes.  Two 
tablespoonfuls  of  carbon  bisulphide 
may  be  poured  into  each  box  once 
,  a  month  to  kill  the  pests. 

Butterflies  and  some  other  in- 
sects with  _«^~_ 
large  wings 
should  have 
their  wings 
spread 
a  while  fresh, 
so  t  h  at 
they  will 
dry  and 
remain  in 
that  posi- 

wnen 


FlG-    8.  -Rearing    cage 
made  of  a  flower  pot  and 

a  lantern  globe. 


FIG   7.—  Spreading  board. 

pinned.  A  board  for  spreading  in- 
sects is  shown  in  Figure  7.  For 
more  detailed  instructions,  see 

"  Insect  Life,"  pp.  303-305. 

CAGES.  —  A   small   rearing   cage 


APPENDIX  103 

may  be  made  with  a  flower  pot  and  lantern  globe,  as 
shown  in  Figure  8.  Fill  the  pot  with  earth  and  sink  a 
bottle  in  the  earth  up  to  its  neck,  in  the  center  of  the  pot, 
to  hold  water-soaked  sand  in  which  to  place  the  stems  of 
the  food  plants.  Tie  mosquito  netting  over  the  mouth  of 
the  globe. 


FIG.  9.  —  Battery  jar  aquarium. 


"  A  good  home-made  cage  can  be  built  by  fitting  a  pane 
of  glass  into  one  side  of  an  empty  soap  box.  A  board  3 
or  4  inches  wide  should  be  fastened  below  the  glass  so  as 
to  admit  of  a  layer  of  soil  being  placed  in  the  lower  part  of 
the  cage,  and  the  glass  can  be  made  to  slide,  and  thus  serve 
as  a  door.  The  glass  should  fit  closely  when  shut  to  pre- 
vent the  escape  of  insects." 

"  Many  larvae  when  full  grown  enter  the  ground  to  pass 
the  pupal  state ;  on  this  account  a  layer  of  loose  soil  should 
be  kept  in  the  bottom  of  a  breeding  cage.  This  soil  should 


104 


APPENDIX 


not  be  allowed  to  become  dry,  neither  should  it  be  soaked 
with  water."  For  further  and  full  instructions,  see  "  Insect 
Life,"  pp.  326-335. 

AQUARIA.  —  For  the  breeding  of  aquatic  insects  aquaria 
are  needed. 

"  Small  aquaria  can  be  made  of  jelly  tumblers,  glass  finger 
bowls,  and  glass  fruit  jars,  and  larger  aquaria  can  be  ob- 
tained of  dealers.  A  good  substitute  for  these  is  what  is 
known  as  the  battery  jar  (Fig.  9).  There  are  several 
sizes  of  these,  which  can  be  obtained  of  most  dealers  in 
scientific  apparatus. 


FIG.  10. — Plants  for  an  aquarium;  a,  parrot's  leather;  b,  water  purslane; 
c,  water  starwort ;  d,  e,  stoneworts ;  /,  waterweed, 

"  To  prepare  an  aquarium,  place  in  the  jar  a  layer  of 
sand;  plant  some  water  plants  in  this  sand;  cover  the 
sand  with  a  layer  of  gravel  or  small  stones ;  and  then  add 
the  required  amount  of  water  carefully,  so  as  not  to  dis- 
turb the  plants  or  to  roil  the  water  unduly.  The  growing 
plants  will  keep  the  water  in  good  condition  for  aquatic 
animal  life  and  render  changing  of  the  water  unnecessary. 


APPENDIX  105 

if  the  animals  in  it  live  naturally  in  quiet  water.  Among 
the  more  available  plants  for  use  in  aquaria  are  the  follow- 
ing (Fig.  10) :  — 

"  Waterweed,  Elodea  canadensis; 

11  Bladder  wort,  Utricularia  (several  species) ; 

"  Stoneworts,  Chara  and  Nitella  (several  species  of  each) ; 

"  Water  starwort,  Callitriche  (several  species)  ; 

"  Water  cress,  Nasturtium  officinale; 

"  Frog  spittle,  or  water  silk,  Spirogyra; 

"  A  small  quantity  of  duckweed,  Lemna,  placed  on  the 
surface  of  the  water  adds  to  the  beauty  of  the  aquarium. " 

BIRDS  AND  THEIR  EGGS.  —  We  do  not  believe  in  making 
collections  of  the  skins  and  eggs  of  birds.  We  believe  in 
studying  birds  in  the  green  fields  and  wooded  glens  with  a 
field  glass  and  notebook.  If  a  collection  must  be  made  for 
the  school,  consult  Davie's  "  Methods  in  the  Art  of  Taxi- 
dermy "  and  Bendire's  "  Directions  for  Collecting,  Prepar- 
ing, and  Preserving  Birds'  Eggs  and  Nests." 

Vertebrates  and  invertebrates,  other  than  birds,  mammals, 
and  insects,  may  be  preserved  in  85%  alcohol  or  4% 
formalin,  in  glass  jars,  so  that  they  may  be  examined  with- 
out being  handled.  Jars  for  this  purpose  may  be  obtained 
of  dealers  in  laboratory  supplies.  Fish  had  better  be  pre- 
served in  alcohol. 

BOOKS.  —  There  is  no  doubt  that,  in  the  study  of  nature, 
books  are  often  used  too  much.  Yet  a  temperate  use  of 
the  right  kind  of  books  is  a  great  inspiration.  For  example, 
the  author  believes  that  the  fifteen  minutes  spent  now  and 
then  in  reading  to  a  class  short  extracts  from  Kipling, 
Bullen,  Burroughs,  Sharp,  and  others  have  been  very 
profitable  minutes.  There  is  no  more  interesting  descrip- 


106  APPENDIX 

tion  extant  of  squid  and  cod  fishing  than  in  Kipling's 
"Captains  Courageous.7'  Better  still  is  it  for  the  pupils  to 
read  these  books  themselves.  The  author  gives  a  list  of 
books  that  may,  if  read  at  the  proper  times,  impart  life 
and  enthusiasm  to  what  might  otherwise  become  a  monot- 
onous subject.  First  of  all,  however,  we  shall  give  a  list  of 
reference  books  that  may  well  be  in  every  school  library. 

BAILEY,  F.  MERRIAM.  Handbook  of  Birds  of  the  Western 
United  States.  Houghton,  Mifflin,  &  Company,  $3.50. 

BEDDARD,  F.  E.  Text-book  of  Zoogeography.  G.  P. 
Putnam's  Sons,  SI. 50. 

BENDIRE,  CHARLES.  Lifq  Histories  of  North  American 
Birds.  Distributed  by  the  Smithsonian  Institution. 

BENDIRE,  CHARLES.  Directions  for  Collecting,  Prepar- 
ing, and  Preserving  Birds'  Eggs  and  Nests.  Distributed 
by  the  United  States  National  Museum. 

CAMBRIDGE  NATURAL  HISTORY.  Ten  volumes,  The 
Macmillan  Company,  about  $3.50  a  volume. 

CHADBOURNE,  P.  A.  Instinct  in  Animals  and  Men. 
G.  P.  Putnam's  Sons,  $2.50. 

CHAPMAN,  F.  M.  Handbook  of  Birds  of  Eastern  North 
America.  D.  Appleton  &  Company,  $3.00. 

COMSTOCK,  A.  B.  Hints  for  Collecting  and  Preserving 
Insects.  Teacher's  Leaflet  No.  7.  Bureau  of  Nature 
Study,  Ithaca,  N.Y. 

COMSTOCK,  J.  H.  Manual  for  the  Study  of  Insects. 
Comstock  Pub.  Company,  Ithaca,  N.Y.,  $3.75. 

COMSTOCK,  J.  H.  Insect  Life.  D.  Appleton  &  Com- 
pany, $1.75.  » 

COMSTOCK,  J.  H.  AND  A.  B.  How  to  Know  the  Butter- 
flies. D.  Appleton  &  Company,  $2.25. 


APPENDIX  107 

COUES,  ELLIOT.  Key  to  North  American  Birds.  Dana 
Estes  &  Company,  $12.50. 

COWAN,  T.  W.  Natural  History  of  the  Honey  Bee. 
London,  Houlston,  Is.  6d. 

DAVIE,  OLIVER.  Methods  in  the  Art  of  Taxidermy  and 
Nests  and  Eggs  of  North  American  Birds.  Columbus, 
Ohio,  Oliver  Davie  &  Company. 

GAGE,  S.  H.  Life  History  of  the  Toad.  Leaflet  No.  9. 
Bureau  of  Nature  Study,  Ithaca,  N.Y. 

HEILPRIN,  A.  Geographical  and  Geological  Distribution 
of  Animals.  D.  Appleton  &  Company,  $2.00. 

HOLLAND,  W.  J.  The  Moth  Book.  Doubleday,  Page, 
&  Company,  $4.00. 

HOLLAND,  W.  J.  The  Butterfly  Book.  Doubleday, 
Page,  &  Company,  $3.00. 

HORNADAY,  W.  T.  The  American  Natural  History. 
Charles  Scribner's  Sons,  $3.50. 

HOWARD,  L.  0.  The  Insect  Book.  Doubleday,  Page,  & 
Company,  $3.00. 

HOWARD,  L.  0.  Mosquitoes :  How  they  Live,  etc. 
McClure,  Phillips,  &  Company,  $1.50. 

JORDAN  AND  EVERMANN.  American  Food  and  Game 
Fishes.  Doubleday,  Page,  &  Company,  $4.00. 

JORDAN,  D.  S.  Manual  of  Vertebrate  Animals  of  the 
Northern  United  States.  A.  C.  McClurg  &  Company,  $2.00. 

JORDAN,  D.  S.,  AND  KELLOGG,  V.  L.  Animal  Life. 
D.  Appleton  &  Company,  $1.25. 

KELLOGG,  V.  L.  Elementary  Zoology.  Henry  Holt  & 
Company,  $1.20. 

LUBBOCK,  SIR  JOHN.  On  the  Senses,  Instincts,  and 
Intelligence  of  Animals.  D.  Appleton  &  Company,  $1.75. 


108  APPENDIX 

LUCAS,  F.  A.  Animals  of  the  Past.  McClure,  Phillips, 
&  Company,  $2.00. 

MIALL,  L.  C.  The  Natural  History  of  Aquatic  Insects. 
The  Macmillan  Company,  $1.75. 

MORGAN,  C.  L.  Animal  Behavior.  Longmans,  Green, 
&  Company,  $3.50. 

NEEDHAM,  J.  G.  Elementary  Lessons  in  Zoology. 
American  Book  Company,  $.90. 

PARKER,  T.  J.  A  Course  of  Instruction  in  Zootomy. 
The  Macmillan  Company,  $2.25. 

PARKER  AND  HASWELL.  Text-book  of  Zoology.  Two 
volumes.  The  Macmillan  Company,  $9.00. 

POTTS,  EDWARD.  Monograph  of  the  Fresh-water  Sponges. 
Obtainable  from  the  author  at  228  South  Third  Street, 
Philadelphia,  Pa.,  $1.00. 

POULTON,  E.  B.  The  Colors  of  Animals.  D.  Appleton 
&  Company,  $1.75. 

RILEY,  C.  V.  Directions  for  Collecting  and  Preserving 
Insects.  Smithsonian  Institution,  Washington,  D.C.,  $.25. 

RIVERSIDE  NATURAL  HISTORY.  Six  volumes.  Hough- 
ton,  Mifflin,  &  Company,  $30.00. 

ROGERS,  MARY  FARRAND.  Life  in  an  Aquarium.  Leaflet 
No.  11,  Nature  Study  Bureau,  Ithaca,  N.Y. 

SEMPER,  K.  Animal  Life  as  affected  by  the  Natural 
Conditions  of  Existence.  '  D.  Appleton  &  Company,  $2.00. 

STONE,  W.,  AND  CRAM,  W.  E.  American  Animals. 
Doubleday,  Page,  &  Company,  $3.00. 

Obtain  from  your  senator  or  representative,  Vols.  4,  6, 
9,  and  10,  of  the  first  session  of  the  47th  Congress.  These 
volumes  contain  illustrated  articles  on  the  whale,  seal, 
etc.  Also  ask  your  congressman  for  the  reports  of  the 


APPENDIX  109 

United  States  Fish  Commission.  They  contain  much 
valuable  and  interesting  information  on  the  habits,  life 
histories,  and  manner  of  catching  many  of  the  common 
food  fishes. 

The  foregoing  list  of  books  will  make  a  very  good  stand- 
ard reference  library  for  a  high  school.  The  books  in  the 
following  list  are  of  quite  a  different  tone  and  are  valua- 
ble in  injecting  an  element  into  the  work  that  will  add 
interest,  zest,  and  enthusiasm.  Besides,  they  are  good 
literature. 

BULLEN,  FRANK  T.  The  Cruise  of  the  Cachelot.  Read 
it  in  connection  with  the  study  of  the  whales.  D.  Appleton 
&  Company,  $1.50. 

BURROUGHS,  JOHN.  Squirrels  and  Other  Fur  Bearers. 
Hough  ton,  Mifflin,  &  Company,  $1.00. 

COMSTOCK,  A.  B.  Ways  of  the  Six-footed.  Ginn  & 
Company,  $.40. 

INGERSOLL,  ERNEST.  Wild  Neighbors.  Harper  &  Bros., 
$1.50. 

LONG,  WILLIAM  J.  Wilderness  Ways.  Ginn  &  Com- 
pany, $.60. 

ROBERTS,  CHARLES  G.  D.  The  Kindred  of  the  Wild. 
L.  C.  Page  &  Company,  $2.00. 

SETON,  ERNEST  THOMPSON.  Wild  Animals  I  Have 
Known.  Charles  Scribner's  'Sons,  $2.00. 

SHALER,  N.  S.  Domesticated  Animals.  Charles  Scrib- 
ner's Sons,  $2.50. 

SHARP,  D.  L.  Wild  Life  near  Home.  The  Century 
Company,  $2.00. 

W^ALLIHAN,  A.  S.  Camera  Shots  at  Big  Game.  Double- 
day,  Page,  &  Company,  $5.00. 


110  APPENDIX 

WEED,  CLARENCE  M.  Nature  Biographies.  Doubleday, 
Page,  &  Company,  $1.35. 

WEED,  C.  M.,  AND  DEARBORN,  M.  Birds  in  their  Rela- 
tions to  Man.  J.  B.  Lippincott  Company ,  $2.50. 

DEALERS  IN  NATURAL  HISTORY  SUPPLIES.  —  The  follow- 
ing dealers  can  furnish  the  apparatus  needed  in  the  work 
outlined  in  this  book :  — 

Bausch  and  Lomb  Optical  Company,  Rochester,  N.Y. ; 
Queen  &  Company,  1010  Chestnut  Street,  Philadelphia, 
Pa.;  Eimer  &  Amend,  205-211  Third  Ave.,  New  York; 
Spencer  Lens  Company,  546  Main  St.,  Buffalo,  N.Y. ;  Kny 
Scheerer  Company,  17  Park  Place,  New  York ;  and  others 
perhaps  nearer  the  reader  than  any  of  these  named. 

For  specimens  needed  in  demonstrations  and  dissections, 
apply  to  any  of  the  following :  — 

H.  H.  &  C.  S.  Brimley,  Raleigh,  N.C. ;  Marine  Biological 
Laboratory,  Woods  Hole,  Mass.;  and  Ward's 'Natural 
Science  Establishment,  Rochester,  N.Y. 


OUTLINES    OF    BOTANY 

1 1. 00 

By    ROBERT    GREENLEAF    LEAVITT,  A.M.,    of 

the  Ames  Botanical  Laboratory.     Prepared  at  the  request 
of  the  Botanical  Department  of  Harvard  University 


Edition  with  Gray's  Field,  Forest,  and  Garden  Flora $1.80 

Edition  with  Gray's  Manual  of  Botany 2.25 


THIS  book  covers  the  college  entrance  requirements  in 
botany,  providing  a  course  in  which  a  careful  selection 
and  a  judicious  arrangement  of  matter  is  combined  with 
great  simplicity  and  definiteness  in  presentation. 
^|  The  course  offers  a  series  of  laboratory  exercises  in  the 
morphology  and  physiology  of  phanerogams  ;  directions  for  a 
practical  study  of  typical  cryptogams,  representing  the  chief 
groups  from  the  lowest  to  the  highest  ;  and  a  substantial 
body  of  information  regarding  the  forms,  activities,  and  re- 
lationships of  plants  and  supplementing  the  laboratory  studies. 
^J  The  work  begins  with  the  study  of  phanerogams,  taking 
up  in  the  order  the  seed,  bud,  root,  stem,  leaf,  flower,  and 
fruit,  and  closing  with  a  brief  but  sufficient  treatment  of 
cryptogams.  Each  of  the  main  topics  is  introduced  by  a 
chapter  of  laboratory  work,  followed  by  a  descriptive  chapter. 
Morphology  is  treated  from  the  standpoint  of  physiology  and 
ecology.  A  chapter  on  minute  structure  includes  a  discussion 
of  the  cell,  while  another  chapter  recapitulates  and  simplifies 
the  physiological  points  previously  brought  out. 
^[  The  limitations  of  the  pupil,  and  the  restrictions  of  high 
school  laboratories,  have  been  kept  constantly  in  mind.  The 
treatment  is  elementary,  yet  accurate  ;  and  the  indicated 
laboratory  work  is  simple,  but  so  designed  as  to  bring  out 
fundamental  and  typical  truths.  The  hand  lens  is  assumed 
to  be  the  chief  working  instrument,  yet  provision  is  made  for 
the  use  of  the  compound  microscope  where  it  is  available. 


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CHEMISTRIES 

By  F.  W.  CLARKE,  Chief  Chemist  of  the  United  States 
Geological  Survey,  and  L.  M.  DENNIS,  Professor  of 
Inorganic  and  Analytical  Chemistry,  Cornell  University 


THESE   two  books  are   designed   to   form  a  course  in 
chemistry  which  is  sufficient  for  the  needs  of  secondary 
schools.    The  TEXT- BO  OK  is  divided  into  two  parts, 
devoted   respectively    to    inorganic    and    organic    chemistry. 
Diagrams  and  figures  are  scattered  at  intervals  throughout  the 
text  in  illustration  and  explanation  of  some  particular  experi- 
ment or  principle.    The  appendix  contains  tables  of  metric 
measures  with  English  equivalents. 

^f  Theory  and  practice,  thought  and  application,  are  logically 
kept  together,  and  each  generalization  is  made  to  follow  the 
evidence  upon  which  it  rests.  The  application  of  the  science 
to  human  affairs,  its  utility  in  modern  life,  is  also  given  its 
proper  place.  A  reasonable  number  of  experiments  are  in- 
cluded for  the  use  of  teachers  by  whom  an  organized  laboratory 
is  unobtainable.  Nearly  all  of  these  experiments  are  of  the 
simplest  character,  and  can  be  performed  with  home-made 
apparatus. 

^j  The  LABORATORY  MANUAL  contains  127  experi- 
ments, among  which  are  a  few  of  a  quantitative  character.  Full 
consideration  has  been  given  to  the  entrance  requirements  of 
the  various  colleges.  The  left  hand  pages  contain  the  experi- 
ments, while  the  right  hand  pages  are  left  blank,  to  include 
the  notes  taken  by  the  student  in  his  work.  In  order  to  aid 
and  stimulate  the  development  of  the  pupil' s  powers  of  observa- 
tion, questions  have  been  introduced  under  each  experiment. 
The  directions  for  making  and  handling  the  apparatus,  and 
for  performing  the  experiments,  are  simple  and  clear,  and  are 
illustrated  by  diagrams  accurately  drawn  to  scale. 


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and  problems  on  the  application  of  these  laws,  and  laboratory 
experiments  to  be  performed  by  the  students. 
^[  The  text,  which  is  accurate  and  systematically  arranged, 
presents  the  essential  facts  and  phenomena  of  physics  clearly 
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whole,  the  curve,  electrical  measurements,  induced  currents, 
the  dynamo,  and  commercial  applications  of  electricity. 
^"  The  illustrative  experiments  and  laboratory  work,  intro- 
duced at  intervals  throughout  the  text,  are  unusually  numerous, 
and  can  be  performed  with  comparatively  simple  apparatus. 
Additional  laboratory  work  is  included  in  the  appendix,  to- 
gether with  formulas  and  tables. 


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SCIENTIFIC    MEMOIRS 

Edited  by  JOSEPH  S.  AMES,  Ph.D.,  Johns  Hopkins 
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THE  FREE  EXPANSION  or  GASES.  Memoirs  by  Gay-Lussac,  Joukj  and 
Joule  and  Thomson.  Edited  by  Dr,  J.  S.  Ames.  $0.75, 

PRISMATIC  AND  DIFFRACTION  SPECTRA.  Memoirs  by  Joseph  von  Fraun- 
hofer.  Edited  by  Dr.  J.  S.  Ames.  $0.60. 

RONTGEN  RAYS.  Memoirs  by  Rontgen,  Stokes,  and  J.J_  Thomson.  Edited 
by  Dr.  George  F.  Barker.  $0.60. 

THE  MODERN  THEORY  OF  SOLUTION.  Memoirs  by  Pfeffer,  Van't  Hoff, 
Arrhenius,  and  Raoult.  Edited  by  Dr.  H.  C.Jones.  $1.00. 

THE  LAWS  OF  GASES.  Memoirs  by  Boyle  and  Amagat.  Edited  by  Dr. 
Carl  Barus.  #0.75. 

THE  SECOND  LAW  OF  THERMODYNAMICS.  Memoirs  by  Carnot,  Clausius, 
and  Thomson.  Edited  by  Dr.  W.  F.  Magie.  $0.90. 

THE  FUNDAMENTAL  LAWS  OF  ELECTROLYTIC  CONDUCTION.  Memoirs 
by  Faraday,  Hittorf,  and  Kohlrausch.  Edited  by  Dr.  H.  M. 
Goodwin.  $0.75. 

THE  EFFECTS  OF  A  MAGNETIC  FIELD  ON  RADIATION.  Memoirs  by  Fara- 
day, Kerr,  and  Zeeman.  Edited  by  Dr.  E.  P.  Lewis.  $0.75. 

THE  LAWS  OF  GRAVITATION.  Memoirs  by  Newton,  Bouguer,  and  Cav- 
endish. Edited  by  Dr.  A.  S.  Mackenzie.  $1.00. 

THE  WAVE  THEORY  OF  LIGHT.  Memoirs  by  Huygens,  Young,  and 
Fresnel.  Edited  by  Dr.  Henry  Crew.  $1.00. 

THE  DISCOVERY  OF  INDUCED  ELECTRIC  CURRENTS.  Vol.  I.  Memoirs  by 
Joseph  Henry.  Edited  by  Dr.  J.  S.  Ames.  $0.75. 

THE  DISCOVERY  OF  INDUCED  ELECTRIC  CURRENTS.  Vol.  II.  Memoirs 
by  Michael  Faraday.  Edited  by  Dr.  J.  S.  Ames.  $0.75. 

THE  FOUNDATIONS  OF  STEREO-CHEMISTRY.  Memoirs  by  Pasteur,  Le  Bel, 
and  Van't  Hoff,  together  with  selections  from  later  memoirs  by 
Wislicenus,  and  others.  Edited  by  Dr.  G.  M.  Richardson.  $1.00. 

THE  EXPANSION  OF  GASES.  Memoirs  by  Gay-Lussac  and  Regnault.  Edited 
by  Prof.  W.  W.  Randall.  $1.00. 

RADIATION  AND  ABSORPTION.  Memoirs  by  Prevost,  Balfour  Stewart, 
Kirchhoff,  and  Kirchhoff  and  Bunsen.  Edited  by  Dr.  DeWitt  B. 
Brace.  $1.00. 


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LESSONS     IN     PHYSICAL 
GEOGRAPHY 

By  CHARLES  R.   DRYER,  M.A.,  F.G.S.A.,  Professor 
of  Geography,  Indiana  State  Normal  School 


SIMPLICITY  and  accuracy  constitute  two  of  the  chief 
O  merits  of  this  text  -book.  Moreover,  much  of  the  gene- 
ralization, which  is  the  bane  of  all  text-books,  has  been 
avoided.  The  physical  features  of  the  earth  are  grouped 
according  to  their  causal  relations  and  the  functions  which  they 
perform  in  the  world  economy.  The  characteristics  of  each 
group  are  presented  by  means  of  a  typical  example,  which  is 
described  in  unusual  detail.  Many  realistic  exercises  are  in- 
troduced to  direct  the  student  how  to  study  the  thing  itself, 
whenever  practicable,  or  some  experimental  or  pictorial  repre- 
sentation of  it.  These  exercises  include  both  field  and  labora- 
tory work,  and  should  be  made  fundamental  rather  than 
supplemental. 

^|  The  order  of  general  topics  is  the  Planet  Earth,  the  Land, 
the  Sea,  the  Atmosphere,  and  Life,  and  each  topic  is  treated 
with  such  fullness  that  it  enables  the  teacher  who  has  not 
had  a  special  course  in  geography  to  teach  the  subject  in- 
telligently. At  intervals  throughout  the  book  there  are  in- 
troduced discussions  of  the  consequences  which  follow  the 
conditions  described,  and  chapters  upon  Life,  containing  a  full 
treatment  of  the  controls  exerted  by  geographical  conditions 
upon  plants,  animals,  and  men. 

^[  The  book  is  eminently  readable.  The  style  is  less  formal 
and  dogmatic  than  is  usual  in  a  scientific  text-book,  and 
approaches  that  which  a  teacher  uses  in  conversation.  The 
appendix  contains  directions  for  laboratory  exercises,  full  in- 
formation in  regard  to  the  best  material  for  the  equipment  of 
a  geographical  laboratory,  and  a  reference  list  of  the  available 
literature  upon  the  subject.  The  book  is  profusely  illustrated. 


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ON     METEOROLOGY 


ELEMENTARY  METEOROLOGY    .     .     .     .11.50 

By  FRANK  WALDO,  Ph.D.,   late  Junior  Professor  in 
the  United  States  Signal  Service 


IN  this  book,  embodying  the  latest  phases  of  the  science,  and 
the  most  approved  methods  of  teaching,  the  treatment, 
as  far  as  practicable,  is  inductive.  The  fact  that  meteor- 
ology is  largely  an  observational  study  is  kept  constantly  in 
mind.  The  student  is  introduced  to  rational  methods  of 
investigation,  and  taught  to  observe  weather  conditions,  to 
account  intelligently  for  successive  changes  in  the  weather,  and 
to  make  intelligent  predictions  for  himself.  Special  chapters 
are  devoted  to  the  meteorology  of  the  United  States,  in  which 
the  work  of  the  Weather  Bureau  is  clearly  explained.  The 
charts  and  illustrations  are  an  important  feature. 


OBSERVATIONS  AND  EXERCISES  ON  THE 

WEATHER $0.30 

By  JAMES  A.  PRICE,  A.M.,  Instructor  in  Physiography 
in  High  School,  Fort  Wayne,  Ind. 


THIS  laboratory  manual  is  intended  to  supplement  the 
recitation  work  in  physical  geography  and  meteorology 
in  secondary  schools.  It  consists  of  a  blank  weather 
record  covering  forty  days,  to  be  filled  in  by  the  pupil  from  his 
own  observations  of  the  thermometer,  barometer,  hygrometer, 
weather  gauge,  clouds,  winds,  etc.  Following  these  tables 
is  a  series  of  ingeniously  devised  exercises  whereby  the  pupil, 
from  the  observation  and  study  of  his  weather  record,  is  led 
to  deduce  many  of  the  general  principles  of  meteorology. 
The  instruments  necessary  for  the  observations  are  few  and 
inexpensive. 


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ESSENTIALS    IN    HISTORY 


ESSENTIALS  IN  ANCIENT  HISTORY  .     .     $1.50 

From  the  earliest  records  to  Charlemagne.  By  ARTHUR 
MAYER  WOLFSON,  Ph.D.,  First  Assistant  in  History, 
DeWitt  Clinton  High  School,  New  York. 

ESSENTIALS  IN   MEDIAEVAL  AND   MODERN 
HISTORY $1.50 

From  Charlemagne  to  the  present  day.  By  SAMUEL 
BANNISTER  HARDING,  Ph.D.,  Professor  of  Euro- 
pean History,  Indiana  University. 

ESSENTIALS  IN  ENGLISH  HISTORY    .     .     $1.50 

From  the  earliest  records  to  the  present  day.  By 
ALBERT  PERRY  WALKER,  A.M.,  Master  in  His- 
tory, English  High  School,  Boston. 

ESSENTIALS   IN   AMERICAN    HISTORY  .     #1.50 

From  the  discovery  to  the  present  day.  By  ALBERT 
BUSHNELL  HART,  LL.D.,  Professor  of  History, 
Harvard  University. 


THESE  volumes  correspond  to  the  four  subdivisions  re- 
quired   by  the   College  Entrance   Examination   Board, 
and  by  the  New  York  State  Education  Department. 
Each  volume  is  designed  for  one  year's  work.      Each  of  the 
writers  is  a  trained  historical  scholar,  familiar  with  the  con- 
ditions and  needs  of  secondary  schools. 

^|  The  effort  has  been  to  deal  only  with  the  things  which 
are  typical  and  characteristic;  to  avoid  names  and  details 
which  have  small  significance,  in  order  to  deal  more  justly 
with  the  forces  which  have  really  directed  and  governed  man- 
kind. Especial  attention  is  paid  to  social  history,  as  well  as 
to  the  movements  of  sovereigns  and  political  leaders. 
^[  The  books  are  readable  and  teachable,  and  furnish  brief 
but  useful  sets  of  bibliographies  and  suggestive  questions. 
No  pains  have  been  spared  by  maps  and  pictures,  to  furnish 
a  significant  and  thorough  body  of  illustration,  which  shall 
make  the  narrative  distinct,  memorable,  and  clear. 


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